Hervé IV of Donzy
Hervé IV of Donzy (1173–1223) was a French nobleman and participant in the Fifth Crusade. By marriage in 1200 to Mahaut de Courtenay (1188–1257), daughter of Peter II of Courtenay, he became Count of Nevers.
In a dispute over the château de Gien with Peter of Courtenay, Hervé came to a settlement in 1199, having defeated and captured his overlord Peter at Cosne-sur-Loire. After Peter's death in 1219, he became Count of Auxerre and Tonnerre also; with Philip II, Marquis of Namur and Robert de Courtenay contesting Auxerre. He acquired Liernais also, in 1210.
Hervé and his countess were active in developing the Nivernais, his lands around Donzy adjoining the Nivernais and Burgundy. In 1209 they founded a Carthusian abbey at Bellary. He reconstructed the château Musard, Billy-sur-Oisy, around 1212-5. The priory at Beaulieu was founded in 1214.
In 1217 he took part in the French invasion of England.
His death has often been attributed to poison.
The daughter of Hervé and Mahaut, Agnès de Donzy (1205–1225), married in 1217 Philippe de France, eldest son of the Dauphin, the future Louis VIII of France. Philippe died the following year. Agnès then married Guy de Châtillon (died 1226), with a daughter Yolande de Châtillon, who married Archambaud IX de Bourbon. Mahaut married Guy de Forez in 1226.
- By some accounts she accompanied him on the Crusade; but others report a divorce in 1213..
- Cawley, Charles, LATIN EMPERORS, Foundation for Medieval Genealogy, retrieved August 2012,[better source needed];  (French language); the deal was ratified by Philip Augustus.
- ; he was baron de Donzy, comte de Gien, seigneur de Cosne, de Châtel-Censoir, de Montmirail, d'Alluye, d'Authou, de Vierzon et de Brou, comte de Nevers et de Tonnerre.
- Histoire de l'abbaye de Bellary
- Château, Musard, Mahau de Courtenay, Hervé VI
- http://www.vaux-yonne.com - Rix en quelques mots !
- Récit des Comtés d'Auxerre, de Nevers et de Tonnerre
- Battle of Bouvines (27 July 1214)