Apart from its defensive role, the Porte du Croux obtained a commercial role through the taxes on consumer products that entered through the city gates. An “alderman” (elected municipal representative) administered the district attached to the Porte du Croux. An old fortified medieval entrance, it was rebuilt as we know it today between 1394 and 1398. Previously, a gate at this location was already documented in 1194, the date of the construction of the ramparts by Pierre de Courtenay. A front door was built in 1422.
The defensive role of the Porte du Croux ceased definitively in 1578 after the aldermen had walled it up during the religious wars. It was then used as an archive for the abbess of Notre-Dame Abbey, then as a powder depot during the revolutionary period.
In 1847, abandoned, it was bought by the Baron de Vertpré who donated it to the municipality under the condition of restoration and the creation of a museum of antiquities of the Nièvre.
It was in 1862 that the building was classified as a historic monument