Europeans began arriving in Mexico during the Spanish conquest of the Aztec Empire; and while during the colonial period most European immigration was Spanish (mostly from northern provinces such as Cantabria, Navarra, Galicia and the Basque Country,), in the 19th and 20th centuries European and European-derived populations from North and South America did immigrate to the country. According to 20th- and 21st-century academics, large-scale intermixing between the European immigrants and the native Indigenous peoples produced a Mestizo group which would become the overwhelming majority of Mexico's population by the time of the Mexican Revolution. However, according to church and censal registers from the colonial times, the majority (73%) of Spanish men married Spanish women. Said registers also put in question other narratives held by contemporary academics, such as European immigrants who arrived to Mexico being almost exclusively men or that "pure Spanish" people were all part of a small powerful elite, as Spaniards were often the most numerous ethnic group in the colonial cities and there were menial workers and people in poverty who were of complete Spanish origin.