The Pre-Sultan (c. 8350 – 7370 BCE) is sometimes called Sultanian. The site is a settlement surrounded by a massive stone wall over high and wide at the base (see Wall of Jericho), inside of which stood a stone tower (see Tower of Jericho), over high, containing an internal staircase with 22 stone steps and placed in the centre of the west side of the tell. This tower and the even older ones excavated at Tell Qaramel in Syria are the oldest ever to be discovered. The wall may have served as a defence against flood-water, with the tower used for ceremonial purposes. The wall and tower were built during the Pre-Pottery Neolithic A (PPNA) period around 8000 BCE. For the tower, carbon dates published in 1981 and 1983 indicate that it was built around 8300 BCE and stayed in use until c. 7800 BCE. The wall and tower would have taken a hundred men more than a hundred days to construct, thus suggesting some kind of social organization. The town contained round mud-brick houses, yet no street planning. The identity and number of the inhabitants of Jericho during the PPNA period is still under debate, with estimates going as high as 2,000–3,000, and as low as 200–300. It is known that this population had domesticated emmer wheat, barley and pulses and hunted wild animals.