That simple taco found its way to San Vicente via a man called Marcial Balderas. In 1948, when he was only 14 years old, Balderas moved from San Vicente, then an agricultural village, to Mexico City, part of the first wave of mass migration that, in just a few decades, would turn it into the world's largest metropolis. Shortly after arriving, Balderas met a woman called Cristina Mendoza, originally from Guadalajara, who, he says, taught him how to make what she referred to as tacos sudados, literally "sweated tacos." (Where she learned to make them he never found out). Each morning, he would fold his tortillas around hot fillings, pack them tightly into a basket lined with hand-embroidered napkins, and take them to a sidewalk in front of a school in the neighborhood of Tlatelolco to sell them.