Task: Question Understanding
Input (English): Context : At the time, the House of Trastámara was the most prestigious in Europe, due to the rule of the Catholic Monarchs, so the alliance of Catherine and Arthur validated the House of Tudor in the eyes of European royalty and strengthened the Tudor claim to the English throne via Catherine of Aragon's ancestry. 
Question : What is Catherine of Aragon's spouse's name?
Output (English): spouse