The Château de Montsoreau is said to be the first french Renaissance Building. The building marks the transition from military architecture to palace or chateau. Large windows, numerous chimneys, and the great care that taken to sanitation problems, are some of the characteristics of this new style of building. The castle central dwelling was built directly in the Loire riverbed. Unusually, Two right-angled wings looking like square towers were built a few years later, at a time when round towers were usually built, this odd choice prefigures the corner pavilions of classical architecture. A spiral staircase probably existed before the current Renaissance staircase.