Bricks and urbanism in the Indus Valley rise and decline

Abstract

The Indus Valley Culture (IVC), often denoted by its major city Harappa,
spanned almost two millennia from 3200 to 1300 BC. Its tradition reaches back
to 7000 BC: a 4000 year long expansion of villages and towns, of trading
activity, and of technological advancements culminates between 2600 and 1900 BC
in the built-up of large brick-built cities, writing, and political authority;
the IVC emerges as one of the first great civilizations in history. During the
ensuing 600 years, however, key technologies fall out of use, urban centers are
depopulated, and people leave the former core areas of the IVC; although many
different hypotheses have been put forward, a conclusive causal chain for this
decline has not yet been established. We here combine literature estimates on
brick typology, and on urban area for individual cities; in the context of the
existing extensive data on Harappan artifact find sites and put in their
chronological order, the combined narratives told by bricks, cities, and
extent, can provide a new point of departure for discussing the possible
reasons for the mysterious decline.

Full text

Bricks and urbanism in the Indus Valley rise and decline
Aurangzeb Khan
∗
and Carsten Lemmen
Helmholtz-Zentrum Geesthacht, Germany
Abstract.
The Indus Valley Culture (IVC), often denoted by its major city Harappa, spanned almost two
millennia from 3200 to 1300 BC. Its tradition reaches back to 7000 BC: a 4000 year long expansion of villages
and towns, of trading activity, and of technological advancements culminates between 2600 and 1900 BC in
the built-up of large brick-built cities, writing, and political authority; the IVC emerges as one of the first great
civilizations in history. During the ensuing 600 years, however, key technologies fall out of use, urban centers
are depopulated, and people leave the former core areas of the IVC; although many different hypotheses have
been put forward, a conclusive causal chain for this decline has not yet been established. We here combine
literature estimates on brick typology, and on urban area for individual cities; in the context of the existing
extensive data on Harappan artifact find sites and put in their chronological order, the combined narratives
told by bricks, cities, and extent, can provide a new point of departure for discussing the possible reasons for
the mysterious decline.
1. Introduction
In the 1850s, ancient bricks stolen from ruins near
Harappa, a town adjacent to the River Ravi in Punjab,
Pakistan, attracted archaeological investigation. The
bricks were first thought to be part of a Buddhist site,
until Marshall (1924) attributed them to an indigenous
civilization of South Asia, the Indus Valley Culture
(IVC, 3200–1300 BC), whose brick architecture ex-
tends back to 7000 BC and the valleys of Baluchistan
(Possehl, 1990; Jarrige et al., 1995; Kenoyer, 1998).
The building material for the villages and cities
of the IVC was predominantly mud brick. Only in
the Mature phase were baked bricks used in quantity,
especially for walls and floors exposed to water (Pos-
sehl, 2002; Datta, 2001). This phase of baked bricks
coincides with the the urban phase of the IVC, with
many large cities as opposed to the predominant vil-
lage settlements before and after the Mature phase.
The urban phase also spans the period where all key
technologies of the IVC, including writing, shell orna-
∗
Corresponding author. Helmholtz-Zentrum Geesthacht,
Max-Planck-Straße 1, 21502 Geesthacht, Germany.
Tel.: +49 4152 87-1521, Fax.: +49 4152 87-2020, Email.: au-
rangzeb.khan@hzg.de
ments, weights, and seals are present; these fall out of
use with deurbanization after 1900 BC (e.g., Kenoyer,
1998; Datta, 2001; Possehl, 2002; Law, 2007).
At the height of the Indus Civilization, there is an
intimate relationship between key technologies, build-
ing material, and cities. Or, translated into the so-
cial realm, between social and political organization,
craftsmanship, and life style. The investigation of the
combined evidence for technologies, material, and
cities could then possibly inform us about the social,
political, or organizational factors involved in its de-
cline. We reconstruct here the chronological dynamics
of brick usage by typology, and of urban area for the
entire IVC from individual estimates. Combined with
existing extensive data on Harappan artifact find sites
a narrative of the rural-urban relationship of Harap-
pans emerges. This relationship can provide a new
point of departure for discussing the possible reasons
for the mysterious IVC decline.
2. Indus Valley chronology and extent
Several chronologies have been developed for the
IVC, of which those by Kenoyer (1998) and by Pos-
sehl (2002) are widely employed. From these two,
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BRICKS AND URBANISM IN THE INDUS VALLEY RISE AND DECLINE KHAN & LEMMEN
we differentiate an Early Neolithic period, consist-
ing of the Kili Ghul Muhammad (7000–5000 BC)
and Burj Basket-Marked (5000–4300 BC) phases,
a pre-Harappan or Developed Neolithic period with
the Togau (4300–3800 BC) and Hakra-Kechi (3800–
3200 BC) phases, the IVC proper represented in the
Early (3200–2600 BC), Mature (2600–1900 BC), and
Late (1900–1300 BC) Harappan phases, and a post-
Harappan phase (from 1300 BC).
As the constituent phases have been developed from
local stratigraphies at type sites dispersed throughout
the IVC domain, conflicting phase boundaries, multi-
ple naming for cotemporal phases, and phase overlaps,
a separation in the eight phases named above is overly
simplified and in a way arbitrary; this simplification
is necessary, however, to be able to address the global
developments within the IVC in a common temporal
frame (Fuller, 2006; Gangal et al., 2010; Lemmen
and Khan, 2012). But even if when common tempo-
ral frame is established, the dates given in years BC
should be treated with caution, as more often than
not precise dating has not been performed for most
sites. Here, we rely on previously published local
chronologies (Tab. 1); as the focus of this paper is
not on discussing the divergent local chronologies
and dating problems, we continue our analysis in the
awareness that this chronology is subject to discussion
and further refinements in many places.
The Indus Valley cultural tradition dates back to
7000 BC and the foothills and valleys of Baluchistan.
At the site of Mehrgarh, early food production was
dated to 6500 BC (Jarrige et al., 1995). Already early
villages exhibit a planned layout, and houses were
built of mud bricks. Pottery appears in the Burj pe-
riod, as well as a wide array of tools, domesticates, and
first copper artifacts (Moulherat et al., 2002; Fuller,
2011). From 5000 BC, the occupation area, which
was concentrated in Baluchistan, the Makran coast,
and the western borderlands of the Indus, expand
north- and westward into K.P., Gujarat and the Punjab
plains (Gangal et al., 2010; Lemmen and Khan, 2012).
Use of ornamental pottery and gold emerges, along
with the manufacture of compartmented seals, glazed
steatite, and beads. The use of weight indicates that
trade was important for the pre-Harappan economy.
The first pre-Harappan cities appear as Mehrgarh,
Amri, and Kotdiji before 3500 BC, they are built from
mud (or sun-dried) brick. Many more villages than
cities continue to expand the cultural domain along the
Ghaggar Hakra river and along the Makran coast with
a doubling of sites numbers after 3200 BC(Law, 2007).
Only in this Early phase do baked bricks appear at
few sites, first at Kalibangan, Kotdiji, and Banawali
(Chattopadhyaya, 1996).
At its peak, the mature IVC extended across the
alluvial plains of Punjab and Sindh, Baluchistan, the
Gujarat coast, and the surrounding valleys in Khyber
Pukhtunkhwa (K. P.); in total, it encompassed a vast
area of 1 million km
2
represented by thousands of
individual sites (Fig. 1). Many large cities have been
recognized, amongst them are the sites of Harappa and
Mohenjodaro with approximately 40 000 inhabitants
each (Mcintosh, 2007); total population is estimated at
a few million (Lemmen and Khan, 2012). Its extensive
and long-range trade network connected by sea to
the Sumerian domain and the Arabian peninsula, it
connected by land to the Bampur valley and across
central Asia (Rao, 1965; Boivin and Fuller, 2009; Law,
2011).
After 1900 BC, the trade network collapsed and
weights were disused; large cities were abandoned and
baked brick manufacturing stopped; shell ornaments
and seals were disused, and settlements moved east-
wards into the Ganges valley(Possehl, 2002; Kenoyer,
1998; Datta, 2001). Sites in Gujarat seem to last
longest, but by 1300 BC only few scattered sites re-
main of the IVC (Rao, 1963; Law, 2007; Mcintosh,
2007). The mystery and challenge in IVC scholarship
lies in the unresolved causes for and diverse opinions
about this decline; most popular theories include envi-
ronmental change (e.g., Raikes, 1964; Meher-Homji,
1973; Staubwasser, 2003; MacDonald, 2011), river re-
locations (e.g., Wilhelmy, 1967; Giosan et al., 2012),
or social causes (e.g., Wheeler, 1968; Kenoyer, 2005).
All of these theories, however, suffer from contrast-
ing evidence, interpretation uncertainties, a temporal
mismatch with the decline period, or have been rein-
terpreted to serve a particular political and historical
view (Possehl, 2002; Guha, 2005). Most certainly,
multiple factors contributed to the decline, including
a breakdown of trade and religion (Kenoyer, 2005).
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BRICKS AND URBANISM IN THE INDUS VALLEY RISE AND DECLINE KHAN & LEMMEN
Table 1: Summary of local chronologies used in this study
Chronology Period (BC)
Mehrgarh I 7000–5500
Kili Ghul Moh. 7000–5000
Northern Neolithic
11
3200-1900
Mehrgarh II 5500–4800
Burj Basket-Marked 5000–4300
Mehrgarh III 4800–3500
Togau 4300–3800
Sheri Khan Tarakai 4300–3000
Anarta
3
3500–2600
Hakra Wares 3800–3200
Kechi Beg 3800–3200
Pre-Harappan 3800–3200
Jodhpura
5
2600–1800
Mehrgarh V 3250–3000
Nal 3200–2800
Anjira
1
4300–3200
Sothi-Siswal 3200–2600
Amri-Nal 3200–2600
Ravi 3200–2600
Damb Sadaat 3200–2600
Chronology Period (BC)
Early Harappan 3200–2600
Kulli (Early)
7
3200–2600
Kot Diji 3200–2600
Mehrgarh VI 3000–2800
Shahi Tump
1
3500–3000
Ahar-Banas
3
3000–1500
Mehrgarh VIIC 2800–2600
Dasht
12
2800–2200
Kot Diji (Late) 2600–1900
Kulli 2600–1900
Accharwala
4
2600–1900
Mature Harappan 2600–1900
Uttarpradesh
11
2600–1900
Ganeshwar
5
2600–1800
Quetta
3
2500–1900
Sorath Harappan 2500–1900
Sorath 2500–1600
BMAC 2300–1700
Sorathor 2200–1800
Pre-Prabhas
10
2200–1800
Chronology Period (BC)
Bara
13
1900–1300
Jhukar 1900–1700
Late Sorath 1900–1600
Cemetery H 1900–1500
Rajaput 1900–1300
Late Harappan 1900–1300
Post-urban 1900–1300
Prabhas
10
1800–1500
Rangpur IIB
9
1800–1500
Rangpur IIC
9
1800–1500
Pirak II 1800–1000
Malwa 1700–300
Swat Proto-Historic 1650–1300
Lustrous Red Ware 1600–1300
Complex B 1300–700
Jhangar 1200–1000
Iron Age 1200–1000
Painted Gray Ware 1100–500
Pirak III 1000–700
Zangian 1000–200
Based on Possehl (2002) and Gangal et al. (2010), with changes from
1
Franke-Vogt (2008),
2
Ratnagar (2000),
3
Fuller (2006),
4
Possehl (1999),
5
Kenoyer (2006),
6
Law (2007),
7
Biagi (2011),
8
Shinde et al. (2006),
9
Meadow et al. (1997),
10
Dhavalikar (1984),
11
Possehl (1990),
12
Mortazavi (2011), and
13
Shaffer (1981).
3. Data on bricks and urbanism
3.1. City and town size through time
The classification of settlements into villages, towns,
and cities is not straightforward for the IVC, because
of the unquantified contribution of pastoralist activi-
ties in between settlements(Possehl, 2002). An enclos-
ing wall would classify a settlement as a city, a gated
location with political power over the surrounding ru-
ral area and a central place for the exchange of traded
goods(Kenoyer, 1998); a sufficient population size for
division of labour and an economic and social organi-
zation allowing population growth characterize cities
according to Childe (1950) and Modelski (2003). To
a first degree, a settlement’s area is a proxy for popu-
lation size, and the ratio of its area of a settlement to
the average settlement size an indication of its nodal
position in a trade network.
For nine such nodal places, cities or towns, chrono-
logically resolved size estimates are available. These
are Mehrgarh, Amri, Kotdiji, Harappa, Mohenjodaro,
Lothal, Dholavira, Kalibangan, Ganweriwala, and
Rakhigarhi (Tab. 2). We generated for each of these
cities a continuous time series from the earliest to the
latest area literature estimate. The thus calculated total
urban area only includes are from those 9 cities whose
temporal information is available. For example, some
other large cities, like Tharowarodar, Nagoor, Nin-
dowari, and Lakhueenjodaro have a combined area of
ca. 200 ha during the Mature phase(Possehl, 2002).
3.2. Brick typology
Worldwide, mud bricks were first used in pre-
Harappan time in Mehrgarh from 7000 BC, and baked
brick technology appeared first in the IVC. The baked
brick work is the signature mark of Harappan Bronze
Age technologies. Most of the large cities of the IVC,
i.e. Harappa, Mohenjodaro, Kot Diji, Ganweriwala,
Rakhigarhi, and Lothal were built from both mud and
baked brick (Tab. 3, with the largest baked brick:mud
brick proportion at Mohenjodaro, Possehl 2002). Mud
brick usage precedes baked brick usage, and continues
when baked bricks are not used any more (Datta, 2001;
Chattopadhyaya, 1996) Only one large city, Dholavira,
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BRICKS AND URBANISM IN THE INDUS VALLEY RISE AND DECLINE KHAN & LEMMEN
Table 2: Time-resolved data of the areal extent of 9 cities and towns.
City/Town Area (ha) in period (year BC)
Mehrgarh
1
30 ha 7000–5500; 16 ha 5500–4800; 9 ha 4800–3500; 9 ha 3500–3250; 18 ha 3250–3000
Ganweriwala
1,2,3
79 ha 2600–2250; 81.5 ha 2250–1900; 80 ha 1900–1800
Kalibangan
1
10 ha 2600–2250; 12 ha 2250–1900; 5 ha 1900–1300
Amri
4
10 ha 4300–3800; 30 ha 3800–3300; 20 ha 3300–3200
Lothal
1,5
4.2 ha 2600–2250; 25 ha 2250–1900; 25 ha 1900–1700; 10 ha 1700–1300
Dholavira
6
2 ha 2600–2250; 30 ha 2550–2200; 80 ha 2200–2000;
100 ha 2000–1900; 70 ha 1900–1800; 15 ha 1650–1450
Harappa
1,6
1 ha 3800–3200; 1.5 ha 3200–2800; 32 ha 2800–2600;
100 ha 2600–2200; 150 ha 2200–1900; 100 ha 1900–1800; 8 ha 1800–1500
Rakhigarhi
1
2 ha 3200–2600; 0 ha 2600–1800; 80 ha 1800–1300
Mohenjodaro
1,6,7
5 ha 2900–2600; 75 ha 2600–2250; 200 ha 2250–1900; 100 ha 1900–1700; 20 ha 1700–1300
References:
1
Possehl (2002),
2
Law (2007),
3
Agrawal (1993),
4
Possehl (1990),
5
Rao (1963),
6
Kenoyer (1998), and
7
Dani (1971)
is built completely from mud bricks (Bisht, 1982; Pos-
sehl, 2000).
Quite the opposite, most villages and towns in the
IVC were built from stones and mud bricks (Datta,
2001; Chattopadhyaya, 1996). The few exceptions
are Jalilpur, Kalibangan, and Chanhudaro, where also
baked bricks were used (Mughal, 1970; Joshi et al.,
1984; Flam, 1981). Chanhudaro stands out in this list,
as there is no preceding mud-brick only phase for this
site (Flam, 1981).
3.3. Spatiotemporal distribution of Harappan sites
We used the Indus Google Earth Gazetteer (version
August 2008) compiled by Law (2007) for the geolo-
cation of artifacts relating to the Indus valley. From
this database of 3348 dates from 2125 distinct find
sites, we use here the cultural attribution and location
of those 3102 Neolithic and Bronze Age sites and
dates that are in the spatial and temporal domain of
our study. For the pre-Harappan phases, the Kili Ghul
Muhammad, the Burj Basked-Marked, the Togau (and
Sheri Khan Tarakai), and the Hakra/Kechi Beg (in-
cluding Anarta complexes), we extracted 374, 421,
706, and 1039 dates, respectively. For the Harappan
Early, Mature and Late phases, we obtained 1321,
1848, and 1085 dates, respectively (Fig. 2). To our
knowledge, this gazetteer is the most extensive and
the most representative data set of lithic and metal
artifacts of the Indus valley tradition. It has been used
to investigate the trade and distribution networks of
the IVC by its author (Law, 2011).
4. Bricks and urbanism in IVC rise and decline
4.1. Bricks
Bricks constitute a large part of the archaeological
material left behind by the Indus civilization. These
bricks provide information on the number and spatial
distribution of settlements, on the extent and density of
settlements, and on the relation between dense urban
and sparse rural areas. Even more, bricks inform about
structural and symbolic functions in ancient societies
(Kenoyer, 2006)
Brick work literally lays the foundations of the In-
dus Valley cultural tradition when it emerges in after
7000 BC. Its prominent role, however, is taken by
baked bricks, which were manufactured only from the
end of the Early to the beginning of the Late phase,
a distinct and narrow 1500 year period within the al-
most six millennia of this tradition. Why this shift
to and away from bricks? Baked bricks are a supe-
rior technology over sun-dried bricks, and while most
of the building continued to be performed with mud
bricks, baked bricks were extensively used where their
improved strength was important (Possehl, 2002).
Baked bricks are less affected by long-term water
exposure; this water resistance became a key factor in
the expansion of Harappan villages and cities into the
Punjab flood plains. Their sustained establishment in
the flooding zones of the river plains was facilitated
by baked brick technology. The protective function
of baked bricks is exemplified by the massive and
technically refined flood protection structures around
Mohenjodaro and Harappa (Kenoyer, 1998). Baked
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BRICKS AND URBANISM IN THE INDUS VALLEY RISE AND DECLINE KHAN & LEMMEN
Table 3:
Data on Harappan location where information on brick typology and usage time is available. Dates
correspond to local stratigraphic chronology (Tab. 1).
Location Mud brick Baked brick References
Harappa 3800–1300 2500–1800 Datta 2001; Chattopadhyaya 1996; Possehl 2002
Mohenjodaro 2900–1300 2600–1800 Datta 2001; Chattopadhyaya 1996
Kot Diji 3200–1300 2600–1800
Bisht 1982; Bhan 1975; Datta 2001; Chattopadhyaya 1996;
Possehl 2002
Banawali 3200–1000 2600–1800 Bisht 1982; Bhan 1975; Datta 2001
Ganweriwala 2900–1800 2600–1900 Mughal 1997
Rakhigarhi 3200–1300 2200–1600 Nath 2001
Dholavira 3200–1450 Possehl 1979; Bisht 1982; Possehl 2002
Lothal 2600–1300 2500–1500 Rao 1979; Datta 2001
Mehrgarh 7000–3800 Jarrige et al. 1995; Datta 2001; Possehl 2002
Kili Ghul Muhammad 6000–1800 Fairservis 1956; Datta 2001; Chattopadhyaya 1996
Sur Jangal 4300–3800 Fairservis 1959; Datta 2001
Rana Ghundai 4000–1800
Ross 1946; Stein 1929; Datta 2001; Chattopadhyaya 1996;
Lamberg-Karlovsky 1972
Damb Sadat 3200–2600 de Cardi 1983; Datta 2001; Chattopadhyaya 1996
Mundigak 3300–1800 Ball and Gardin 1982; Datta 2001; Chattopadhyaya 1996
Amri 3200–1800 Flam 1981; Datta 2001; Chattopadhyaya 1996
Chanhudaro 2500–1700 Flam 1981; Majumdar 1934; Possehl 2002
Sanghol 1800–500 Bhan 1975; Joshi et al. 1984; Datta 2001
Bhagwanpura 2600–1500
Bhan and Shaffer 1978; Joshi et al. 1984; Datta 2001; Chat-
topadhyaya 1996
Nal Samadhi 3000–(2200)
1
Rai and Kumar 1989; Chattopadhyaya 1996
Kalibangan 3200–1000 2600–1800 Thapar 1979; Joshi et al. 1984; Datta 2001; Possehl 2002
Jalilpur 3300–1500 2800–1800 Mughal 1970
Gumla 5000–3200 Dani 1971
Rehman Dheri 2900–1800 Dani 1971
1
Date estimated by authors.
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BRICKS AND URBANISM IN THE INDUS VALLEY RISE AND DECLINE KHAN & LEMMEN
(a) 7000-3200 BC
Neolithic
(b) 3200-2600 BC
Early phase
(c) 2600-1900 BC
Mature phase
(d) 1900-1600 BC
early Late phase
(e) 1600-1300 BC
later Late phase
(f) 1300-700 BC
post-Harappan
Figure 2:
Spatial and temporal distribution of find sites of the Indus valley cultural tradition from Law (2007)
with the chronology from Tab. 1. Sites with baked brick usage are highlighted with large square
symbols.
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BRICKS AND URBANISM IN THE INDUS VALLEY RISE AND DECLINE KHAN & LEMMEN
brick usage for all buildings in the flood-prone city
Chanhudaro demonstrates the importance of baked-
brick technology for flood protection.
Not only for flood protection, but generally for ur-
banism baked bricks seem to have been a precondition:
almost all large cities of the Mature phase (Dholavira,
Chanhudaro, and Mohenjodaro being the exception)
are built with a combination of sun-dried and baked
bricks. Quite likely, their use as house foundations and
for the lining of sewage systems was crucial for the
sustained growth of villages in to large cities. Besides
for protection from water, baked bricks were used for
city walls and citadels in the four largest cities Mo-
henjodaro, Harappa, Ganweriwala, Rakhigarhi, and
several minor cities and purpose sites (Smith, 2006).
Punjab
Sindh
Gujarat
Baluchistan
K. P.
Kashmir
Rajasthan
Arabian Sea
Indus
Mature phase
Late phase
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Figure 1:
Spatial extent of the Indus Valley Culture
in the Mature and Late phases with major
urban centers and towns mentioned in the
text: 1 Kalibangan, 2 Rakhigarhi, 3 Ba-
nawali, 4 Rehman Dheri, 5 Naru Waro
Dharo, 6 Amri, 7 Harappa, 8 Rana Ghundai,
9 Jalilpur, 10 Sur Jangal, 11 Gumla,
12 Lothal, 13 Mohenjodaro, 14 Lakhueen-
jodaro, 15 Chanhudaro, 16 Bhagwanpura,
17 Damb Sadat, 18 Nindowari, 19 Mundi-
gak, 20 Mehrgarh, 21 Ganweriwala, 22 Kot
Diji, 23 Sanghol, and 24 Dholavira.
The temporal distribution of the number of cotem-
poral sites using bricks (from Tab. 3, shown in Fig. 3a)
shows four different dynamic regimes of overall brick
usage: (1) a steady and slow increase characterizes
the Neolithic periods, (2) a sudden doubling and steep
increase of brick sites is typical for the Early Harap-
pan phase; this (3) levels out during the Mature phase
before it is (4) reversed by a strong decrease during
the Late and post-Harappan phases. Only during the
Mature phase, most of the sites investigated use also
baked bricks; and baked bricks decline entirely during
the Late phase.
The baked brick technology, once invented, re-
quired skilled labor, standards, and natural resources.
All these were available within the IVC during the
Mature phase. There is no evidence for scarcity of
natural resources for baked brick production. Fine silt
(and water) abounded in the river plains of Punjab and
Sindh. Irrespective of potential climatic changes, the
gallery forests along the perennial rivers provided an
ample and steady supply of fire wood: Meher-Homji
(1973) estimated that only 200 hectares of riverine for-
est were required to supply baked bricks long enough
to support the large city of Mohenjodaro (which was
mostly built from baked bricks) for 100 years.
The second requirement—standards—has been a
long-standing and featured trademark of Harappan
masonry. Possehl (2002) calls the typical ratio of
4:2:1 (length to width to height) of Indus Valley bricks
the “Indus proportion”. The adherence to this ratio
was ensured by the use of standardized molds. While
this ratio was typical at Harappa for large bricks, some
cities, like Kalibangan, also used different brick ratios
(3:2:1) (Mcintosh, 2007). During the Late phase, brick
dimensions diverged away from the Indus proportion
(Datta, 2001; Mcintosh, 2007).
Beyond the molds, the standards are also preserved
in the craftsmen’s tradition and in social norms. The
deviation from the standard in the Late phase could
therefore point to a changed social norm, or to the lack
of craftsmen to keep up the traditional brick manufac-
ture. This third requirement of skilled labour refers
to the craftsmanship and knowledge needed to choose
the correct silts, mix the appropriate quantities of silts
and water, and find the right temperature and roast-
ing time to produce maximum strength bricks. Did
craftsmen and their skills migrate? There is no direct
evidence. The late appearance of bricks in the Gu-
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BRICKS AND URBANISM IN THE INDUS VALLEY RISE AND DECLINE KHAN & LEMMEN
jarat sites, predominantly Lothal after 2200 BC (Rao,
1965), however, could be evidence for increased need
of brick producers in the south of the IVC, when at
the same time the size of Harappa already started to
decrease. Outside of the IVC baked brick technology
appears in Susa (eastern Gulf of Persia), where they
are used in monumental construction from 1800 BC
(Gallet et al., 2006).
4.2. Urban center
The contrast between rural and urban lifestyle in the
IVC is best portrayed by the distribution of find sites
on the one hand, and by the area of the largest cities on
the other hand (Fig. 3b). Between 5000 and 1300 BC,
there is a continuous occupation of between 400 and
1000 cotemporal sites recorded in the Law (2007)’s
database. The increase from pre-Harappan to the Early
phase is around 300 sites, and another increase by 300
sites occurs from the Early to the Mature phase. The
number of sites falls slowly to 800 during the Late
phase: the Indus Valley decline cannot be detected in
this dataset.
It is, however, not the number, but rather the spatial
pattern of sites which changes through pre-Harappan
(Lemmen and Khan, 2012) and IVC phases (Joshi
et al., 1984; Gangal et al., 2010). At the end of the
Mature phase, only along the Ghaggar-Hakra river
sites disappear whereas new sites emerge in the upper
Ganges reaches. By 1500 BC, most of the Baluchis-
tan and Punjab sites have disappeared, while sites in
Gujarat and along the Ganges are still present. The Gu-
jarat complex disappears by 1000 BC (Gangal et al.,
2010); these authors also note that during the termi-
nal Mature phase many small sites replace large sites;
they attribute this to a movement of population from
urban centers into villages.
In contrast to the number of (small) sites, the data
on large urban centers and their area (Tab. 2) ex-
hibits strong variations. The combined urban area
of large cities was below 40 ha until 2600 BC. The
few pre-Harappan and early Harappan cities (e.g.,
Kalibangan, Amri Nal) were small, in contrast to the
many and large cities of the Mature phase, where the
largest cities were Mohenjodaro, Harappa, Ganweri-
wala, Dholavira, and Rakigarhi, each of them between
80 and 200 ha. Total urban area is 450 ha in the first
half of the Mature phase, and increases by another
1000200030004000500060007000
early mature late
Time (year BC)
City planning
Mud bricks
Pottery
Faience
Seals
Weights
Baked bricks
Writing
Shell ornaments
Continued
200
400
600
800
1000
Number of artifact sites
100
200
300
400
500
Total urban area (ha)
Urban area
Artifact sites
1000200030004000500060007000
0
5
10
15
20
Time (year BC)
Number of brick sites
Mud and baked
Baked fraction
c) Technologies
b) Cities & sites
a) Bricks
Figure 3:
(c, bottom) Brick typology in IVC cities,
shown as the number of sites employing
mud bricks, or employing both mud and
baked bricks (Tab. 3). (b, middle) The rural-
urban contrast, shown as the total urban area
(from Tab. 2) and the number of Indus ar-
tifact find sites from Law (2007). (c, top)
Introduction, presence and expiration of key
Harappan technologies (Kenoyer, 1998; Pos-
sehl, 2002). Arrows show a continuation of
technology in successor cultures.
50% after 2300 BC.
From the Early to the Mature, and within the Ma-
ture phase, the growth in urban area by far exceeds
the slow dynamics of the number of settlements. This
discordance points to an intensification, a population
growth within or movement towards the urban cen-
ters. Mirroring this intensification, the drastic de-
crease from 750 in the Mature to 100 ha urban area
in the Late phase is not accompanied with a decrease
of the site numbers: the IVC’s population did not de-
Manuscript submitted to the American Journal of Archeology, March 7, 2013 Page 8

BRICKS AND URBANISM IN THE INDUS VALLEY RISE AND DECLINE KHAN & LEMMEN
Table 4:
Simplified mirroring of key Harappan tech-
nologies in social relations
Technology Social relation
Baked bricks ↔ skilled labour
Weights ↔ trade links
Seals ↔ moral authority
Writing ↔ administration
Shell ornaments ↔ elite status
crease, but rather moved from the cities into smaller
(and many) villages
How is the brick dynamics reflected in the urban
area? Both baked bricks and urban centers existed
almost exclusively in the Mature phase, and both ex-
perienced a strong increase before and decrease after-
wards, pointing to a strong correlation between these
two aspects of urbanism. It is difficult—considering
the temporal uncertainties and low number of sites
considered—to establish a temporal sequence between
the two. With the current data, the baked brick in-
crease seems to lead the urbanization, which would
confirms the role of baked bricks as a prerequisite
for urban centers. The temporal uncertainty in the
chronology, however, would need to be decreased for
a better quantification of the phase relationship be-
tween baked bricks and urban area.
4.3. Urban mind
For the Harappan urban mind, baked brick technol-
ogy represents one of the most important characteris-
tics. With the baked-brick stimulated rise of urbanism,
dense population were possible which stimulated in-
novation (Lemmen, 2012); Mature phase technologies
like writing and shell ornaments flourished (Fig. 3c).
The IVC was centrally organized, an empire under
common rule. Priestly elites seem to have exerted their
power rather by moral authority than force; temples,
palaces and evidence for warfare are absent from the
archaeological record (Piggott, 1950; Ratnagar, 2000).
The coherence provided by a moral authority may also
be a decisive factor in ensuring the brick dimensions
standard.
Harappa was also a closed society: Skull fea-
tures from prehistoric cemeteries indicated that ur-
ban Harappans differed from surrounding villagers;
apparently, social practice discouraged mixing with
people outside the city and promoted endogamy (Bar-
tel, 1979)
1
.
Skills, trade, authority, and elite status are social di-
mensions which can be mapped to the material culture
(Tab. 4). For example, the symbolism that held to-
gether Harappan society is mirrored in its seals. Elite
status is expressed by shell ornaments. The Indus
script has not been deciphered, the existence of a writ-
ing system, however, points to use for accounting
and administration. Thus, the decline in baked brick
manufacturing is not merely a loss of one specific
technology, but also represents a considerable loss of
symbolism (Possehl, 2002).
5. Insights for the decline
Social disruptions at the beginning of the Late phase
put an end to religion and trade. The changed burial
pattern points to a different belief system; additional
layers of glaze are used in distinctive pot burials, and
glass making and bead drilling techniques were al-
tered. Trade with the Swat region ceased and resulted
in a decline of shell working. This has been inter-
preted as a disturbance of the elite structure (Ratnagar,
2000; Kenoyer, 2006; Nichols et al., 2008). Postcra-
nial injuries on excavated skulls point to interpersonal
violence among Harappan elites (Robbins Schug and
Gray 2012, but not Mohenjodaran, Kennedy 1984),
and some cities were (partly) burned, like Kotdiji,
Gumla, Nausharo, or Amri (Possehl, 2002).
Could the environmental changes that have been put
forward be responsible for the social upheavals? Arid-
ity and river relocation seem credible for the Ghaggar
Hakra area (Staubwasser, 2003; Giosan et al., 2012);
floods occurred in cities in Sindh: a total of 5 m silt,
composed of up to 2 m thick individual deposits in
Mohenjodaro shows the consequence of inundations
from the middle of the Mature to the end of the Late
phase; multiple alternating cultural and silt deposit
layers indicate rebuilding and renewed floods in this
city (Raikes, 1964; Pruthi, 2004).
Even if one ignores the contrasting evidence, the
interpretation uncertainties, and the temporal mis-
matches with the decline period of the suggested en-
vironmental factors, there seems to be no environ-
1
Even today, endogamy prevails in South Asian populations and
preserves genetically distinct tribes (Chaubey et al., 2007)
Manuscript submitted to the American Journal of Archeology, March 7, 2013 Page 9

BRICKS AND URBANISM IN THE INDUS VALLEY RISE AND DECLINE KHAN & LEMMEN
mental reason that could explain the demise of urban
centers and relocation of villages from Punjab and
Baluchistan. Rather, social causes, like an internal
political struggle, which lead to the visible change in
the Harappan elite system (Kenoyer, 2005) should be
investigated.
We propose that a changed elite structure would
also explain the loss of urban coherence, the diverging
brick standards, and the depopulation of cities. More-
over, a changed elite seemed to have not been able, or
not to have been willing, to continue baked brick man-
ufacturing and the maintenance of the flood protection
structures in Punjab and Sindh, rendering their cities
vulnerable to flooding at least from 1700 BC
2
. If we
take into account that elites were replaced by people
originally from outside the IVC, their unfamiliarity
with local environmental conditions and protection
needs, or their different management priorities could
have exacerbated the problem of neglected flood pro-
tection. Looking at the brick dynamics tells us about
social dynamics.
6. Conclusion
We provide here a novel integrative view of IVC site
distribution, its urban-rural contrast, and the dynamics
of brick usage and urban size to find new points of de-
parture for interpreting the IVC decline. We find that
despite a large geographic change of the site distribu-
tion, the number of sites and—to first approximation—
population does not change much between the Early,
Mature, and Late phases. Urban area and baked bricks,
however, change dramatically in the material culture,
as do their social counterparts administration, elite
structure, and religion. By concentrating on the cities,
we point to primarily social reasons as a starting point
for further investigations on the IVC decline.
Acknowledg ements
Funding for this research has been provided by
the Deutsche Forschungsgemeinschaft’s priority pro-
gramme Interdynamik (SPP 1266), the PACES pro-
gram of the Helmholtz Association of German Re-
search Centres, and by the Pakistan Higher Education
2
Baked brick structure on average need to be replenished at
200 year intervals in the pertaining climate conditions.
Commission. We are grateful to K.W. Wirtz for stimu-
lating ideas to and a critical analysis of a prior version
of this manuscript.
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