Here you have the presentation about the Hispanic Momarchy during the 16th and 17th centuries:
And this is the family tree of the Hispanic Monarchs, starting from the Catholic Monarchs until Philip V. As you can see, endogamous relations were common, in orede to preserve alliances. There were cases of: marriages:
- between cousins, like the one of the Catholic Monarchs (both belonged to the Trastámara dynasty) or Charles I and Isabella of Portugal.
- between aunts and nephews, like the one between Philip II and his aunt Mary Tudor (Catherine of Aragón and Henry VIII's daughter)
- between uncles and nieces, like the one between Philip II and Anna of Austria or the one between Philip IV and Mariana of Austria.
Everything was allowed for the continuation of the dynasty, but this inbreeding had seroius consequences, with handicaped children. Charles II, a disabled monarch, was the culmination of this marriage policy.