However, in 1304 he weakened his brother John's position by leading an offensive of Flemish troops which then occupied Holland and the Sticht.

In Guy's absence, the Fresingen seized power in Utrecht with the support of the guilds, whose privileges they fixed in the "Gildenbrief" of 9 May 1304.

On 14 September 1305, the guilds' regime had to capitulate to bishop Guy (who had been released), but from then on the city retained a high degree of autonomy.

He personally managed the possessions of the lordships of Aemstel and of Woerden, and as such granted town privileges to Amsterdam in 1306.

He was buried in Utrecht Cathedral and his tomb, damaged during the iconoclasm in the 16th century, still survives.