House of Châteaudun

The House of Châteaudun is a medieval lineage that once possessed the Viscounty of Châteaudun, the County of Perche, and the County of Anjou.

Origin of the House of Châteaudun
The House of Châteaudun descended from Gauzfred I (or Geoffrey I) whom Count Theobald I of Blois made Viscount of Châteaudun in 956. Recent research makes him a direct-line agnatic descendant of the Frankish family Rorgonides. For a list of the Counts and Viscounts of Châteaudun, see the article Counts of Châteaudun.

Branches of the House of Châteaudun
The House of Châteaudun split in two distinct branches. Descended from Fulcois du Perche, probably the second son of Gauzfred I, were:
 * The lineage of the Counts of Perche, extinct by 1217, with Thomas du Perche;
 * The line of viscounts of Châteaudun, extinct by 1249, with Geoffrey VI of Châteaudun;
 * The lineage of the counts of Anjou, who acquired the land by the marriage of a grandson of Fulcois, Geoffrey II, Count of Gâtinais with Ermengarde of Anjou, heiress of the House of Ingelger. Their great-grandson in direct agnatic line will be Geoffrey V, Count of Anjou. The Plantagenets are descended from this line.

Genealogy
Note: The dotted lines represent hypothetical relationships. It is not clear whether Hugh, Archbishop of Tours, and Adalaud of Château-Chinon are sons or grandsons of Geoffrey I of Châteaudun. Some sources say that Geoffrey had a son called Hugh, who was himself viscount of Châteaudun, and both the Archbishop of Tours and the Lord of Château-Chinon would in turn be his sons. The number of people called "Hugh" who were viscounts of Châteaudun is thus unclear, and the numbering of each viscount with this name could be wrong by 1. The parentage of Fulcois is also disputed. Some sources put him as the son of Geoffrey I of Châteaudun. Others claim he was his grandson-in-law through marriage to a granddaughter of Geoffrey called Melisende.