On returning to Flanders with his army, the couple was accompanied by Philip I of Namur, Zeger, and John of Nesle, châtelain of Bruges.

[5] Zeger was part of the negotiations, which resulted in the treaty of the bridge of Wendin, signed February 24, 1211 and granting Louis and his heirs the towns of Aire and Saint-Omer.

On August 9, 1212, whether due to beneficence or the demands of the people, Zeger granted citizens of the city of Ghent (really the bourgeois) the privileged to annually renew their aldermen.

At this time, Zeger assisted Louis VIII, Philip's son, in his seizure of the towns of Bailleul, Steenvorde, and several other places.

In revenge, Ferdinand sacked and plundered Saint-Omer, Guinness, Artois, Sanchu, and Lens, in acts described as particularly vicious, as well as destroying Zeger's new castle at Hesdin.

These events led to the decisive Battle of Bouvines, which the French won, and Ferdinand was taken prisoner and brought, for a time, to the tower of the Louvre.

[11] In the later years of his life, Ziger is believed to have been a charitable lord and good administrator, assisting in the building of bridges over the waters allowing the better connection of Ghent neighborhoods Briel and Over the Reke (the location of Saint Bavo Abby).