Much of what is known about him comes from `` Libro de descripción de verdaderos retratos de illustres y memorables varones '' ( Book of the Description of the True Portraits of Illustrious and Memorable Men ) ( 1599 ) by Francisco Pacheco .
Much of what is known about him comes from the book `` Libro de descripción de verdaderos retratos de illustres y memorables varones '' ( Book of the Description of the True Portraits of Illustrious and Memorable Men ) , which was written in 1599 by Francisco Pacheco .