Kings & Queens of Castile
There were four rulers of the kingdom of Castile during the period corresponding with the reign of the Tudors up until 1556, when Philip II, on death of his father Charles V, became King of a united Spain.
| Monarch | Dates of Reign | Spouse(s) |
| Isabella I | 15 January 1475 – 26 November 1504 | Ferdinand II, King of Aragon |
| Juana I | 26 November 1504 – 12 April 1555 | Philip von Hapsburg, Duke of Burgundy |
| Philip I (in right of his wife) | 26 November 1504 – 25 September 1506 | Juana I of Castile |
| Charles I (known as Charles V from his title as Holy Roman Emperor) | 23 January 1516 – 16 January 1556 | Isabella of Portugal |
