Geoffrey IV of Thouars

Geoffrey IV of Thouars (c. 1125–1173), third son of Viscount Aimery V and Agnes of Poitiers, succeeded his brother William I as viscount in 1150. In 1156 he backed Geoffrey Plantagenet's claim to Anjou against Henry II of England and raided Henry's partisans.

In 1158 Henry besieged Thouars and stormed the supposedly impregnable castle in three days; Geoffrey fled, and the walls were dismantled at Eleanor of Aquitaine's request. He later recovered his lands, rebuilt the fortress and pilgrimaged to Santiago de Compostela. He died in 1173, and his son Aimery VII succeeded him.