He went to Spain in 1600, where he studied law at the University of Salamanca. He continued his studies towards a Licentiate in Law—roughly equivalent to a modern master's degree—which he finished in 1605, without, however, taking the degree. Instead, he practiced law for a while in Seville, then in 1608 went back to Mexico, and in 1609 received the licentiate from the University of Mexico. He completed his studies for his doctorate fairly soon thereafter, but never received the degree, in all likelihood because of the rather substantial costs attached to the ceremony. He worked as a legal adviser for a while, as an advocate, and as an interim investigating judge, all the while trying repeatedly and unsuccessfully to gain a teaching chair at the University.