Actually, my first post was a lie. The title doesn't really say all. I was just tired and wanted to get the idea out of my head before going to sleep.
Basically, the scenario is that either:
a. William Adelin marries Matilda, heiress of Boulogne, instead of Matilda of Anjou.
OR
b. William Adelin survives/avoids the White Ship disaster, but Matilda of Anjou dies at some point and Matilda of Boulogne is married to William Adelin instead of Stephen of Blois.
Of course, this would mean giving up the peace/alliance with the Counts of Anjou. If so, Matilda of Anjou might be married to someone else, like William Clito.
Would the King of France even allow the Normans to take Boulogne in such a way?
What prompts his father to seek an alliance with Bolougne instead of Anjou?
Prestige maybe? Matilda of Boulogne's grandfather was a companion of William the Conqueror, and her father and uncles were all famous crusaders (and in Godfrey and Baldwin's cases, the first rulers of Jerusalem).
Hmm interesting she's also be an heiress so more land
Yes, there also the land. But I just remembered that she and William Adelin are first cousins. Both their mothers were daughters of Malcolm III of Scotland and Margaret of Wessex. There is the possibility of a papal dispensation, but I'm not sure if Pope Calixtus would have been willing to grant it.
Hmm, weren't those becoming more common at this point in time?