Ferdinand of Aragon Marries Isabella of Castile
An 18-year-old queen defies her half-brother's wishes and marries within a week of meeting her groom, setting up the union of Spain's two largest kingdoms
Quick facts
- Bride
- Isabella of Castile (1451-1504), age 18
- Groom
- Ferdinand II of Aragon (1452-1516), age 17
- Location
- Valladolid, Castile
- Union of crowns
- 1479, after the War of Castilian Succession
What happened
Isabella, heir to the throne of Castile, wanted Ferdinand of Aragon as her husband because uniting two neighboring kingdoms with similar customs and laws made political sense for Castile. Her half-brother King Henry IV had approved other suitors and required his consent to any marriage, so Isabella wrote asking permission. Henry never answered. She married Ferdinand anyway on 19 October 1469 in Valladolid, where the two had met for the first time only days earlier. Because Ferdinand and Isabella were second cousins, both descended from John I of Castile, they needed a papal dispensation from Sixtus IV to marry under canon law. The 1469 Marriage Concession that accompanied the wedding stated that Castile belonged to Isabella alone: Ferdinand agreed he would never separate their children from her and that the couple's main residence would be Castile.
Why it matters
Henry and nobles opposed to an Aragonese king in the Castilian court rejected Isabella's claim and tried to install Henry's daughter Juana instead, triggering the War of Castilian Succession. Isabella won that war by 1479, and that same year Castile and Aragon were formally joined as one kingdom under the two monarchs, creating the political base from which Spain would fund Columbus, complete the Reconquista, and build a global empire within a generation.
How we know
World History Encyclopedia's biography of Isabella I, drawing on modern scholarship including Henry Kamen's history of Spain 1469-1714, gives the marriage date, the papal dispensation, and the 1469 Marriage Concession's terms; HISTORY.com's account independently confirms the Valladolid wedding date and its consequence for Spanish unification.
Sources
- HISTORY.com. Ferdinand of Aragon marries Isabella of Castile · Reputable sourcehistory.com · The domain "history.com" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- World History Encyclopedia. Isabella I of Castile · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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