the city, all troops stationed North of the Alps were ordered back to Italy. The garrison and the Roman administration had to abandon the Yverdon camp. The inhabitants of Eburodunum, up to then assigned to live beyond the ramparts, immediately took possession of the Castrum, using it for their own safety. Like this, Eburodunum-Yverdon survived the hard times, until the 15th century. The Castrum was noted in the Notitia Dignitatum (dated c. 420 CE). Savoy era With the lake receding, the ancient town confined to the Castrum had lost its strategic position: no more direct access to the port, or to the new trade routes alongshore. When Peter II of Savoy gradually extended his rule over the Pays de Vaud (Land of Vaud), he managed to impose road tolls as well as port and fishing taxes. He founded the new town ("Ville Neuve") of Yverdon, defended by walls and a castle. Construction works were launched around 1259 and attracted many settlers. Yverdon Castle The imposing main walls and their four towers were erected within a few years. The design of the castle followed the geometric characteristics used for castles set in plains, and had been planned by the young mason and architect Jacques de Saint-Georges. Jacques also planned Caernarvon Castle and built the castle Saint-Georges d'Espéranches, near Lyon. Yverdon's castle used to be the residence of the castellans of the Savoy dynasty, until 1536, followed by the bailiffs of Bern state. In 1798, the Département du Léman became the castle's owner. The Département had been set up by the short-lived "Helvetian Republic" (1798–1803), imposed by Napoleon I. A few years later, Yverdon acquired the castle, to entrust it to Johann Heinrich Pestalozzi and his institute. After 1838, the castle housed a public school. New classrooms were created, especially on the second floor: dividing walls were erected, additional windows changed the severe look of the castle's façade. After 1950, these classrooms were gradually abandoned; the last classes left in 1974. The original medieval structure was then restored. The castle is today a multi-purpose cultural centre, housing a regional museum, a theatre, various conference rooms and the oldest public library of French-speaking Switzerland, founded already in 1763. The library is now part of the castle museum, existing since 1830. Bernese era (1536–1798) The Savoy rulers granted bountiful franchise and liberties to the burghers of Yverdon. The township prospered during the two hundred