Xenophon Hellenica 5.2.5

[5] Its outflow being thus checked, the water rose not only above the foundations of the houses but above those of the city wall. Then as the lower bricks became soaked and failed to support those above them, the wall began first to crack and then to give way. And the Mantineans for a time tried to prop it up with timbers, and sought contrivances to prevent the tower from falling; but when they were no longer able to resist the water, being seized with the fear that if any portion of the encircling wall fell they would become prisoners of war, they offered to agree to tear down their walls. The Lacedaemonians, however, said that they would not make peace with them except on condition that they should also dwell apart in villages. And they for their part, coming to the conclusion that it was necessary, agreed that they would do this also.