Guillemette of Neufchâtel

Guillemette de Neufchâtel (1260–1317) was a French noblewoman, the daughter of Amadeus, Count of Neufchâtel and his wife, Jordanna of Arberg. In 1259, her great-aunt Margaret, married Richard of Neufchâtel-en-Bourgogne. As her dowry, she brought the Lordships of Blamont, Châtelot, Belmont, and Cuisance into the marriage. The Lords of Neufchâtel-en-Bourgogne placed Blamont under the protection of the Duke of Burgundy and thus detached it from Montbéliard.

In 1282, Guillemette married Reginald of Burgundy. They had five children:
 * Othenin "the Mad" (d. 1339), who succeeded her as Count of Montbéliard
 * Agnes of Montbéliard (d. 1377), married Henry I, Count of Montbéliard, who inherited Montbéliard after Othenin's death
 * Joanna (d. 1347), married:
 * Ulrich III, Count of Pfirt
 * Rudolf Hesso, Margrave of Baden-Baden
 * William, Count of Katzenelnbogen
 * Margaret, married William of Antigny, Prince of Sainte-Croix
 * Adelaide, married John II, Count of Chalon-Auxerre

In 1283, her great-grandfather, Theodoric III, Count of Montbéliard (1205–1283) died. He had outlived all his children and in his will, he left the County of Montbéliard to his great-granddaughter Guillemette. Theobald III of Neufchâtel, who was a grandchild of Theodoric III and who wanted Montbéliard for himself, conspired with Reginald's brother Otto IV to have Montbéliard recognized as a fief of Burgundy. To resolve this, Reginald ceded Blamont and Châtelot to Theobald.