The Château de Chaumont is a French castle at Chaumont-sur-Loire, Loir-et-Cher, France.

The first château-fort on this site between Blois and Amboise was a primitive fortress built by Eudes II, Count of Blois, in the 10th century with the purpose of protecting Blois from attacks from his feudal rivals, the counts of Anjou. On his behalf the Norman Gelduin received it, improved it and held it as his own. His great-niece Denise de Fougère, having married Sulpice d'Amboise, the château passed into the family of Amboise for five centuries. The castle was burned to the ground in 1465 in accordance with Louis XI's orders and was later rebuilt by Charles I d'Amboise from 1465-1475 and then finished by his son, Charles II d'Amboise de Chaumont from 1498-1510, with help from his uncle, Cardinal Georges d'Amboise; some Renaissance features were to be seen in buildings that retained their overall medieval appearance.

The Château de Chaumont was purchased by Catherine de Medici in 1560, a year after her late husband Henry II's death. There she entertained numerous astrologers, among them Nostradamus. In 1559 she forced Diane de Poitiers, her late husband's long-term mistress, to exchange the Château de Chenonceau for the Château de Chaumont. Diane de Poitiers only lived at Chaumont for a short while.
(wikipedia)