So let us look at the record, not the reputation, of the wives of Amalric I of Jerusalem: Agnes de Courtney and Maria Comnena.
Why, we do not know. There was the issue of being married within the prohibited degrees on consanguinity, and the issue of the pre-contract with Hugh d’Ibelin, both of which were canonical grounds for divorce. However, the objections of the High Court are not likely to have been legalistic in view of the fact that the High Court explicitly recognized Amalric’s children by Agnes as legitimate. This strongly suggests that the High Court was not uneasy about the legality of Amalric’s marriage but about the character of his wife. Perhaps it was simply the fact that she was a powerful woman, or a notoriously grasping one, or perhaps, as the Chronicle of Ernoul suggests, she was seen as insufficiently virtuous for such an elevated position as queen in the Holy City. Such speculation is beside the point; the naked fact is that Agnes was found unsuitable for a crown by the majority of the High Court. That’s a pretty damning sentence even without knowing the reason, and that’s not just a matter of “bad press.”
Read more about both Maria and Agnes at: Balian and the Kingdom of Jerusalem.
Book I: Knight of Jerusalem, released September 2014.