The constitution was unwritten. Its provisions were expressed in forms known as Rhaetra. The kings were retained. Their power was a guaranty of unity. They maintained the continuity of civic life. Each was a check upon the other. They were held under restraint by the senate. Its composition and functions were now fixed. It met not only to deliberate and advise, but to perform judicial offices. In case of capital offences the kings sat with the elders, each having, with every other member, but a single vote. The members were thirty in number, one for each of the ten clans of each of the three tribes, the kings representing their clans and sitting as equals with equals, though presiding at the sessions. The elders must be of the age of sixty and upward, and were appointed for life. The ancient division of the people was preserved; the households were grouped in thirties, the thirties in clans, the clans in tribes. Their capital was Sparta. It was not a compact walled town. It stretched into the open country and Dorians lived along the entire valley of the Eurotas. Not only those dwelling at the ford of the river, but all were acknowledged as Spartans. The kings were required to summon the heads of the families in the assembly once every month. The place was designated. The session was brief. To encourage brevity there was no provision for seats, but the freemen stood. Elders and other public officers were chosen. Official persons made known new laws, declarations of war and peace and treaties. The people simply voted aye or nay. The decision was according to the volume of sound. The session closed with a military review.