http://agathe.gr/democracy/the_prytaneis.html
The Prytaneis (Executive Committee) The senators administered their meetings themselves. Each tribal contingent in the Boule served in rotation for a period of 35 or 36 days as the Prytaneis, or Executive ... The Prytaneis had their headquarters in the Tholos, a large round building which lay just adjacent to the Bouleuterion. ... Athens, Agora Museum. The circular shape of the Tholos is unusual among public buildings in the Agora. ... The floor was clay. The building was famous for its roof shaped like a sun hat, which gave it the nickname skias, sunshade.
