The 13th century, from 1201 to 1300, started with a massive power struggle. In 1204, the family of Innocent III and the Orsini family took the fighting into the streets. The popes were also involved in the larger struggle for control in Italy. In 1234, Romans led by senator Luca Savelli sacked the Lateran.
In 1277, the Orsini Nicholas III was elected pope. He moved to the Vatican, which was easier to defend that the Lateran. He also made himself a senator, and allowed only Romans to become senators to avoid foreign involvement.