This study is to clarify the basis of the urban planning described in the Spanish colonial law, "Discovery, Colonization and Conquest" promulgated in 1573 by the King, Felipe II, and also to compare it with the practical urban planning before the law's appearance. This law is evidently an early one in the Spanish modern urban history and the previous urban constructions apparently had a great influence on the lawmaking. As the type of the Spanish square "Plaza Mayor" corresponds to the square prescribed here by law, it is full of suggestiveness that this square type has strong relation to the colonial policy also.
