In 1536 was issued the first book printed in Mexico, on a press imported by Mendoza, and put into the hands of one Juan Pablos. In the same year both silver and copper coins were stamped, the latter in the form of an irregular polygon. In 1550 this good ruler sailed away from Mexico, where he had done so much to advance the interests of his royal master. He passed on to take charge of the government of Peru, by a practice which came to be quite common--a sort of diplomatic succession by which the viceroys of New Spain were promoted to the post at Peru. XXI. FRAY MARTIN DE VALENCIA. Don Luis de Velasco, second viceroy of New Spain, made his entrance into the capital with great pomp, at the end of the year 1550. He, like his predecessor, had been selected with care by the orders of Charles V., if not from his personal knowledge, and he brought to his new position qualities as admirable. His first decree was one liberating one hundred and fifty Indians from slavery, who were working chiefly in the mines, and when the objection was raised that this industry would be paralyzed by the step, he stated that the liberty of the Indians was of more importance than all the mines in the world, and that the rents due to the crown were not of such a nature that for them must be interrupted laws human and divine. He established in Mexico, for the security of travellers upon the highway, the tribunal of the Holy Brotherhood, instituted in Spain for the same purpose in the time of Isabella. He founded the Royal University of Mexico, and the Royal Hospital for the exclusive use of the natives. He recognized the capacity of these Indians for developing lands hitherto uncultivated, and, in fact, favored them by every means in his power, while he encouraged the development of all the resources of the country, especially the mines, of which some important discoveries were made in his time. The building of the cathedral at Puebla was pushed with great activity under this viceroy, although the building was not finished until the middle of the next century. Puebla de los Angeles, second in importance in all Mexico to Guadalajara only, receives its name from the tradition that before the light of Christianity was shed on New Spain, the heathen used to see visions of angels marshalled in mighty hosts in the heavens above the spot where the city stands. It is in the Province of Tlaxcalla, where Cortés found his first friends and stanch allies, on the highway between the coast and the capital.