The UNESCO World Heritage Site listing of twelve of Vauban's best fortifications has a historical description for each site. These descriptions are written in French. This is my translation of one of those descriptions.
The citadel and the two forts of the neighbouring commune of Cussac - Fort - Médoc constitute a triptych : their cross-fire blocking the passage on the River Gironde. The citadel is a monumental hybrid group, built between 1686 - 1689, that dominates a pre-existing medieval castle encircling the high town. The 19th century adaptations are artillery batteries on a terrace.
CUSSAC - FORT - MÉDOC
Fort Pate dates from 1689 - 1693 and is situated on a sandbank that appeared in 1670. Fort Médoc was built from 1690 - 1700. Apart from a cistern in 1823, there were no notables modifications.