In 1282 Floris again attacked the troublesome Frisians in the north, defeating them at the battle of Vronen, and succeeded in retrieving the body of his father. After a campaign in 1287–1288 he finally defeated the Frisians. In the meantime he had received Zeeland-bewester-Schelde (the area that controls access to the Scheldt river) as a loan from the Holy Roman King Rudolf I of Germany in 1287, but the local nobility sided with the count of Flanders who invaded in 1290. Floris arranged a meeting with count Guy of Flanders, but he was taken prisoner in Biervliet and was forced to abandon his claims and then set free.