Philip I (22 July 1478 – 25 September 1506), called the Handsome, was the first member of the house of Habsburg to be King of Castile. The son of Holy Roman Emperor Maximilian I by his first wife Mary, Philip was less than four years old when his mother died, and upon her death, he inherited the greater part of the Duchy of Burgundy and the Burgundian Netherlands as Philip IV. In 1496, his father arranged for him to marry Joanna of Castile, second daughter of Ferdinand and Isabella, rulers of Aragon and Castile respectively. Within four years after the wedding, Joanna became heir presumptive to Aragon and Castile, following the deaths of her brother, elder sister and infant nephew during that period. In 1504, aged 27, Philip became king of Castile jure uxoris when his mother-in-law died and Joanna succeeded her. He died only two years later, leaving his wife distraught with grief. Philip was the first Habsburg monarch in Spain, and is the progenitor of every later monarch of Spain, even up to today. He died before his father, and therefore never inherited his father's territories or became Holy Roman Emperor. However, his son Emperor Charles V eventually united the Habsburg, Burgundian, Castilian, and Aragonese inheritances.

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