Immigration to Peru started with the arrival of Spanish settlers during the Colonial Period. Peru is a multiethnic nation formed by the combination of different groups over five centuries. Amerindians inhabited Peruvian territory for several millennia before Spanish Conquest in the 16th century. Spaniards and Africans arrived in large numbers under colonial rule. Many people from European backgrounds mixed with the Amerindians or Asians creating an entirely new demographic group called "mestizos".