Mesoamerica, that is Central and southern Mexico, already had a large indigenous population at European contact in the early sixteenth century, which shaped migration patterns to the colony of New Spain. The Spanish crown restricted immigration to its overseas possessions to Catholics with "pure" ancestry, ("limpieza de sangre"), that is, without the taint of Jewish or Muslim ancestors. Prospective immigrants had to obtain a license from the House of Trade in Seville, Spain, attesting to their religious status and ancestry. So-called New Christians, that is Jewish converts to Catholicism, were forbidden from immigrating for fear they had falsely claimed conversion and were in fact crypto-Jews passing as Christians. During the period when Spain and Portugal had the same monarch (1580-1640), many Portuguese merchants immigrated to Mexico. Religious authorities suspected they were crypto-Jews. The Mexican Inquisition was established in 1571 and arrested, tried, and then turned those convicted over to civil authorities for corporal, sometimes capital, punishment in autos de fe.