EXPLORATIONS IN PISTIROS (Zofia Archibald – z.archibald@liverpool.ac.uk) Important changes were noted in square B21, which provided a coherent interpretation of activities during the 2nd and 3rd phases of Pistiros. At least two built structures, probably of a residential nature, were identified. Pieces of sheet copper alloy, perhaps a set of tools, or material intended for recycling, were found. The presence of iron hammer scale indicates smithing activity. The existence of a built interior in the northernmost part of B21 was confirmed by the presence of a (?) domestic hearth. Near the south-western corner of B21, hard-fired clay fragments began to emerge, fallen face down, as the wall collapsed. This is the clearest evidence of a building with walls made up of packed stakes, overlaid inside and out with clay packing. A cobbled area and some paving slabs existed to the east of the center of B21. To the west of center, a well built in the 3rd phase existed. A ballista ball of 5 minas was found. Stone-throwing catapults came into use during the reign of Alexander the Great and were considerably developed in the early 3rd century BC. On the eastern and northern sides of square D24 a series of burned clay features were noted. It is not clear whether in the 1st phase D24 was used for residential or other purposes. By the 2nd phase residential structures began to be built and continued into the 3rd phase. A series of plaster floor surfaces, associated with several fired clay hearths, began to be constructed during the 4th century BC.