Fired bricks were for millenniums one of the main building materials of masonry structures of the old civilizations developed around Mediterranean basin. In ancient Greece, fired bricks systematically appeared in buildings from the fourth century BC, although ceramic manufacturing was well known since the pre-historic period. In this research study, the morphological, mechanical and physical characteristics, as well as the microstructure of old bricks from Greek monuments dated from the Roman and Byzantine period, are presented. Based on the results, bricks were usually produced manually by using empirical criteria. The bricks of Roman and Byzantine period were mainly plates of 30 x 30 or 30 x 40 cm. Their thicknesses ranged from 2.5 to 6 cm. Different additives were used to improve their properties, such as fine and coarse aggregates or fibrous materials. Generally, old bricks of those periods were of low apparent specific density (1.5-1.8), high absorption (13-30 %) and relatively low compressive strength (5-20 MPa), due to large pores and cracks into their matrix. Due to their surface roughness, the adhesion with the lime mortars was relatively high. A chemical reaction of lime mortar with the amorphous siliceous materials presented in old bricks has often contributed to the improvement of the mortar-brick bond. Since the characteristics and behavior of old bricks of the aforementioned historic periods do not differ much, it implies that both raw materials and the manufacturing techniques used for bricks production had not changed through a long historic period.