I have been working the de Mortimer and Sackville family lines in regards to a Joanne Mortimer (abt. 1313-1338)- (daughter of Roger de Mortimer) - who married a Andrew Sackville (1288-1330). They had issue, a son named Andrew Mortimer (1306-1370). The birth/death dates are all over the map for these folks and tend to lead me to be doubtful of this relationship. Many family trees on RootsWeb cite this union, but do not offer a source and/or record. I am hopeful that I can find proof of this marriage and/or partnership. Any assistance in this matter would be greatly appreciated.