Shirin

Nope. Under canon law, children of putative marriages were (and are) considered legitimate. Granted, there were plenty of medieval nobility who tried to argue otherwise, but their attempts to completely disinherit their children of a putative marriage seldom worked. For specific examples, consider Hugh Bigod, 1st Earl of Norfolk and Marguerite II, countess of Flanders. After Hugh’s death, his second wife, Gundreda de Beaumont, tried to get his son by his annulled marriage to Juliane de Vere declared illegitimate so her sons could inherit instead and failed. Marguerite, meanwhile, tried to completely disinherit her sons by her first husband, Bouchard IV d’Avesnes, but was unable to do so. Instead, the county of Hainaut went to her sons by her first husband and the county of Flanders went to her sons by her second husband.