The ownership of the bed of the Rhone crossing Avignon was a topic of dispute between the papacy and the kings of France in the 14th century. The claims of the French kings for the possession of the whole river gave rise to the interminable Rhône trial, which only ended after the Revolution when Avignon was attached to France in 1791. At that time, the river arm of Avignon dotted with sandbanks forming islets and osier beds was hardly navigable in low water and the configuration of the central islands of Barthelasse and Piot changed according to the floods.