Puerto Rico is an island in the Caribbean region in which inhabitants were Spanish nationals from 1508 until the Spanish–American War in 1898, from which point they derived their nationality from United States law. Nationality is the legal means in which inhabitants acquire formal membership in a nation without regard to its governance type. In addition to being United States nationals, people born in Puerto Rico are both citizens of the United States and citizens of the Commonwealth of Puerto Rico. Citizenship is the relationship between the government and the governed, the rights and obligations that each owes the other, once one has become a member of a nation. Though the Constitution of the United States recognizes both national and state citizenship as a means of accessing rights, Puerto Rico's history as a territory has created both confusion over the status of its nationals and citizens and controversy because of distinctions between jurisdictions of the United States. These differences have created what political scientist Charles R. Venator-Santiago has called "separate and unequal" statuses. History of nationality in Puerto Rico Spanish period (1508–1898) Puerto Rico was a Spanish colony for four hundred years, after Spain first established a settlement on the island in 1508. In accordance with the Laws of the Indies, criollos, persons born in the colonies, had fewer rights than peninsulares, those born in Spain. After a governmental reorganization and propagation of the first Spanish constitution, the 1812 Constitution of Cádiz, Puerto Ricans were defined as persons born on the island and their descendants. They were granted an equal status and representation in the Spanish Parliament. Within two years, the constitution was suspended and absolute monarchy returned, along with the former unequal status based upon place of birth. A Royal Charter issued in 1816, invited foreigners to migrate to Puerto Rico to engage in professions and offered them an opportunity to become Spanish citizens, upon request after establishing residency for five years. Foreigners who established a permanent residence in Puerto Rico were considered subjects, neither Spanish-nationals nor native-born, unless they chose to naturalize. The children born in Puerto Rico derived the status of their fathers. If the father naturalized as Spanish, the children were Spanish nationals and if the father retained his foreign nationality, the children were foreign nationals. Instability in the Spanish Empire resulted in a lengthy period where the Constitution of Cádiz was reinstated and revoked several