In late medieval Europe, marriage diplomacy was an everyday part of political life. As soon as children were born, their parents began planning their lives, assigning each child a designated role relative to their assigned gender and birth order. The first-born son became the heir-apparent, and his wife needed to be of equal bloodlines or higher (for women often married down) or wealthy or well-connected (such as a natural daughter of the pope) to compensate. The second-born son usually became a cleric, while the third-born son became a military captain who married lower-ranking members of the nobility, unless he had made a fortune as a mercenary and found a wife to match his new status.
Daughters were more versatile and could be married into foreign courts and relied upon to become sources of news, trade, and safe passage during wartime. Marriage contracts were often signed before the bride and groom could walk, and were regularly dissolved if better opportunities came along. A dowry was also involved, which included a lavish amount of gold and goods promised to the husband, although not every dowry was promptly paid.
In a nutshell, daughters were married to the ruler who best suited the political objectives of their parents. But this meant they were often sent to kingdoms and duchies where they
