Katherine and her sibings should have had united Europe due to thier marriages. And yet tragedy blighted thier lives.

Isabella was married to  successive kings of Portugal and died in child-birth aged 28. The death of Juan left Isabella heiress to the thrones of Aragon and Castile. The death of her son aged 23 months left her sister Juana the heiress to the joint thrones.

Juan was married to Margaret of Austria and died aged 19 leaving behind a pregnant widow who delivered a stillborn daughter.

Juana ( la loco) was married to Margaret's brother, Philp whom she rapidly feel in love with. Sadly Philip didn't love her as much, and while they had 6 children, his infideility caused Juana much grief. Her succession to the throne of Castile in 1504 was followed in 1506 by the death of Philip. Her devotion to his corpse and the failure of her attempts to rule alone, let Ferdinand back as regent this time. Juana was eventually confined to the Convent of Santa Clara where she died aged 75.

Maria became the second wife of Manuel of Portugal  who her sister Isabella had left a widower. They became the parents of 8 children and  Maria died aged 34.

Katherines was the youngest and became the wife first of Arthur and then his brother Henry.

All 5 children of Ferdinand and Isabella were described as being pale with auburn/gold hair. all were also described as passionate and although thier marriages were based on the need for political alliences, it seems several of them turned into love matches as well.

Ferdinand married a second time and had another son who died hours after birth. He was also the father of several illegitmate children.