Spanish is also known (particularly in Latin America, but increasingly in Spain itself) as Castilian, after the dialect from which modern standard Spanish developed. That dialect arose in Cantabria in the 9th century around the town of Burgos in north-central Spain (Old Castile) and, as Spain was reconquered from the Moors, spread southward to central Spain (New Castile) around Madrid and Toledo by the 11th century. In the late 15th century, the kingdoms of Castile and Leon merged with that of Aragon, and Castilian became the official language of all of Spain. The regional dialects of Aragon, Navarra, Leon, Asturias, and Santander were crowded out gradually and today survive only in secluded rural areas. Galician (a language with many similarities to Portuguese), spoken in northwestern Spain, and Catalan, spoken in eastern and northeastern Spain, were also much reduced but began a resurgence in the late 20th century.