In 1272 Floris unsuccessfully attacked the Frisians in a first attempt to retrieve the body of his father. In 1274 he faced an uprising by nobles led by the powerful lords Gijsbrecht IV of Amstel, Zweder of Abcoude, Arnoud of Amstel, and Herman VI van Woerden, who held lands on the border with the adjacent bishopric of Utrecht (the area of Amsterdam, Abcoude, IJsselstein, and Woerden) at the expense of the bishop. Gijsbrecht and Herman were supported by the craftsmen of Utrecht, the peasants of Kennemerland (Alkmaar, Haarlem, and surroundings), Waterland (north of Amsterdam) and Amstelland (Amsterdam and surroundings) and the West Frisians. He assisted the weak bishop, John I of Nassau, by making a treaty with the craftsmen. The bishop would become dependent on Holland's support, and eventually added the lands of the rebellious lords to Holland in 1279. He gave concessions to the peasants of Kennemerland. Kennemerland was a duneland, where the farmers had far fewer rights than the farmers in the polders. Floris got rid of the Avesnes influence and switched allegiance to the Dampierres.