On the banks of the Oust, Josselin is an important stage on the Route des Ducs. The history of the town is closely linked to that of its castle which overlooks it. In flamboyant Gothic style, it provides an interesting testimony to feudal and Renaissance architecture. Founded in the early 11th century, it is still today lived in by the descendants of the founders, the Rohan family. Take time to stroll around its gardens. They were designed by Achille Duchesne, landscape gardener, who also worked at Vaux-le-Vicomte.