The Château de Lusignan (in Lusignan, Vienne département, France) was the ancestral seat of the House of Lusignan, Poitevin Marcher Lords, who distinguished themselves in the First Crusade and became the royal family of the Kingdom of Jerusalem, the Kingdom of Cyprus, and the Armenian Kingdom of Cilicia.
Lusignan was constructed in the region of Poitou, occupying a natural strongpoint: a narrow promontory that overlooked steep valleys on either side. It was already so impressive in the 12th century that a legend developed to the effect that its founder had faery aid, in the guise of the water spirit Melusine, who built it and its church through her arts, as a gift for her husband Raymondin.
Lusignan at its height, just as it was in the early 15th century, is illustrated in the Très Riches Heures of Jean, duc de Berri, for whom it was a favorite residence until his death in 1416. It rises in the background of the miniature for the month of March (see illustration), clearly shown in perspective, with its barbican tower at the left, the clock tower — with the exterior chute of the garderobe to its right — and the Tour Poitevine on the right, above which the gilded dragon flies, the protective spirit of Melusine. After the duc de Berri's death, Lusignan became briefly the property of John, Dauphin (died May 1417) and then passed to his brother, Charles, the future Charles VII.
First the village, then the town of Lusignan, grew up beneath the castle gates, along the slope; it formed a further enceinte (surrounding fortification) when it too was later enclosed by walls. Lusignan remained a strategically important place in Poitou, in the heart of France: during the French Wars of Religion, about 1574, a plan was made of the castle's defenses; it is in the Bibliothèque Nationale, Paris. In the following century Lusignan was reinforced in the modern manner by Louis XIV's military architect, Vauban. Thus it was a natural structure to be used as a prison. Later it housed a school.