Treaty of Villafáfila

The treaty recognised the incapacity of Ferdinand's daughter and Philip's wife, Joanna the Mad, to reign on her own as Queen of Castile, while allowing her to keep the royal title.

Joanna had succeeded her mother, Isabella the Catholic, who had appointed her husband and co-ruler Ferdinand as regent of Castile in the name of their mentally unstable daughter.

Joanna and Philip immediately added to their titles of "Kings of Indies, Islands and Mainland of the Ocean Sea".

[1] The Indies remained in an ambiguous state from the death of Philip in 1506 to the death of Ferdinand in 1516, being half a personal property of the kings (a "lordship" with absolute power for its lord), and half a kingdom of the Crown (ruled under the laws of the Crown of Castile).

[2] On July 9, 1520 Emperor Charles V incorporated them explicitly into the Crown of Castile and he forbid any future separation.

The Crown of Castile , including extra-peninsular territories in the beginning of the 16th century, briefly united for the first time by the Treaty of Villafáfila (1506) extraofficially united after the death of Ferdinand the Catholic (1516) and formally unified by Charles V in 1520. [ 1 ]