The Mouse Tower (Mäuseturm) is a stone tower on a small island in the Rhine. The Romans were the first to build a structure on this site. It later became part of Franconia, and it fell and had to be rebuilt many times. Hatto II, the Archbishop of Mainz, restored the tower in 968. The story of how it came to be called the 'Mouse Tower' comes from a folk tale (Hatto was being eaten alive by mice in a tower). In 1298 the structure became an official customs collection tower. It was destroyed by a French army in 1689, then rebuilt in 1855 as a Prussian signal tower.
References:The Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.