The exact date of the marriage is unknown, but it was probably in 1051 or 1052, and certainly before the end of 1053, as Matilda is named as William's wife in a charter dated in the later part of that year.
Den præcise dato for brylluppet er ukendt, men det var sandsynligvis i 1051 eller 1052, og med sikkerhed før 1053, da Matilda bliver nævnt som Vilhelms hustru i en charter dateret til slutningen af dette år.