In Greek antiquity, a building for the prytaneis, the administrative officials / inner executive council of a Greek city-state; the town hall of a Greek or Hellenistic city-state. Its origin may be in palaces of tyrants or kings, combining official with residential functions. In Athens, it had a central courtyard with rooms around it; the so-called tholos, a round building as an office, nearby. At Athens, for example, a group of 50 prytaneis ('presidents, chief'), elected by lot and serving for short periods in rotation, acted as committee to the boule ('council'). Ambassadors, distinguished foreigners, and citizens who had done signal service were entertained there. Prytanea are attested at Sigeum in the Troas from the 6th century BC and at various dates in Cyzicus, Erythrae, Priene, Ephesus, Epidamnus, Rhodes, and Olympia.