Those who immigrated to Puerto Rico were given free land and a "Letter of Domicile" with the condition that they swore loyalty to the Spanish Crown and allegiance to the Roman Catholic Church. Most of the new immigrants eventually were settled in the interior of the island which was mostly undeveloped. After residing in the island for five years these European settlers were granted a "Letter of Naturalization" which made them Spanish subjects. Thousands of French and Corsican families (the Corsicans were French citizens of Italian descent) settled in Puerto Rico.