(πρυτάνες), in Grecian antiquity, were the presidents of the Senate, whose authority consisted chiefly in assembling the Senate, which for the most part was done once every day. The Senate consisted of 500, fifty senators being elected out of each tribe; after which lots were cast to determine in what order the senators of each tribe should preside, which they did by turns, and during their presidency were called prytanes. Their period of office was termed a prytany (πρυτανεία), and the building in which they held their meetings was called the prytanium (πρυτανεῖον). However, all the fifty prytanes of the tribes did not govern at once, but one at a time, namely for seven days; and after thirty-five days another tribe came and presided for other five weeks; and so of the rest.