sentences:  During this time not only do leaders such as Zapata and Villa arise, but many Constitutionalists, most of them lawyers, journalists or leading intellectuals, also gained in power and popularity.By the time Díaz agreed to step down and Madero was elected president, the Constitutionalists had gained a power base in most of Mexico's urban population centers, which were mainly located in the center of the country.Zapata held most of the southern regions where the people of indigenous descent were located, and Pancho Villa led the northern areas dominated mostly by ranchers and miners.