Knights and marriage alliances

Foreman: One interesting side light at this time was the use of marriages in diplomacy.

Kings of course were marrying their offspring into other royal families to cement alliances or eventually give themselves claims into foreign territory, but also common or garden routiers were marrying well-off local French women in possession of inheritances. These women got hitched to the routier leaders as a means of preserving their estates from the jealous depredations of their own male family members. It seems that having a bit of rough as a husband was a jolly effective way of preserving your slice of the family fortune.

On a grander scale we might see the marriage of John O'Gaunt and Constance of Castile as an extension of this process. John O'Gaunt was a convenient bit of rough who might preserve Constance's inheritance against her relative, Henry of Trastamara.