Career
Diego Vázquez de Mercado was born in Arévalo, Spain. On November 5, 1603, Pope Clement VIII appointed him Bishop of Yucatán, Mexico. He was consecrated bishop on June 13, 1604 by García de Santa María Mendoza y Zúñiga, Archbishop of México.
May 28, 1608, Pope Paul V appointed him Archbishop of Manila.
While bishop, he was the principal consecrator of Pedro de Arce, Bishop of Cebu (1613), and Principal Company-Consecrator of Alonso de Peralta, Archbishop of Louisiana Plata o Charcas (1609).