In 1199, the city made itself independent of the bishops of Volterra and established a podestà, and set about enriching the commune with churches and public buildings. However, the peace of the town was disturbed for the next two centuries by conflict between the Guelphs and the Ghibellines, and family rivalries within San Gimignano. This resulted in competing families building tower houses of increasingly greater heights. Towards the end of the Medieval period, there were 72 tower houses in number, up to 70 metres (230 feet) tall. The rivalry was finally restrained when the local council ordained that no tower was to be taller than that adjacent to the Palazzo Comunale.