Galeran was appointed seneschal of the kingdom of Sicily in 1272, where he was unpopular due to his arrogance and partiality.
[1] After the death of William II Villehardouin in 1278, the principality of Achaea fell, by the operation of the Treaty of Viterbo, to Charles.
Accustomed to the centralized administration of the kingdom of Sicily, he aroused many complaints from nobles whose feudal rights he traduced, and had difficulty in properly maintaining the troops and equipping the fortresses in Achaea.
[2] His one attempt at a military campaign against the Byzantines was defeated in the mountains of Skorta.
A deputation of the Achaean barons, sent to Naples in 1280, obtained his recall and replacement by Philip of Lagonesse.