阿维拉
The Treaty of the Bulls of Guisando () is the name of a treaty agreed on top of the hill of Guisando near the Bulls of Guisando (located in Ávila, Spain) on 19 September 1468, between Henry IV of Castile and his half-sister Isabella of Castile. In this treaty Isabella was granted the title of Princess of Asturias and therefore became heiress presumptive to the Crown of Castile.