She was the granddaughter of Spanish explorer and conquistador Hernán Cortés, and the great-granddaughter of Aztec Emperor Moctezuma II.
[2] In 1588 in Panuco, Zacatecas, Isabel married Don Juan de Oñate, a Spaniard of Basque ancestry and founder of Santa Fe, New Mexico.
He led a group of 700 settlers and soldiers in 1598 to settle New Mexico two decades before the Mayflower left the port.
Together they had a son and daughter: In 1595, Isabel's husband was ordered by King Philip II of Spain to colonise the upper Rio Grande valley.
Isabel remained behind in Zacatecas when her husband led the expedition in 1598 to what is now the state of New Mexico, and founded the first Spanish settlement in the region.