The Spanish East Indies (Spanish: Indias orientales españolas; Filipino: Silangang Indiyas ng Espanya) were the Spanish territories in Asia-Pacific from 1565 until 1899. They comprised the Philippines, the Mariana Islands, the Caroline Islands (also known as the New Philippine Islands), and briefly also included Spanish Formosa and parts of the Spice Islands. Cebu was the first seat of government, later transferred to Manila. From 1565 to 1821 these territories, together with the Spanish West Indies, were administered through the Viceroyalty of New Spain based in Mexico City.
The King of Spain traditionally styled himself "King of the East and West Indies" (Rey de las Indias orientales y occidentales). After Mexican independence, they were ruled directly from Madrid.
Administrative affairs of the Spanish East Indies were handled by the Captaincy General of the Philippines and the Real Audiencia of Manila. As a result of the Spanish–American War in 1898, most of the islands were occupied by the United States while about 6,000 of the remaining smaller islands were sold to Germany in the German–Spanish Treaty of 1899. The few remaining islands were ceded to the United States when the Treaty of Washington was ratified in 1901.
Spanish contact began on 6 March 1521, when a Spanish expedition led by Ferdinand Magellan reached the Mariana Islands. He named Guam and the other islands "Islas de los Ladrones" (Islands of the Thieves) because the natives came aboard his galleon (the Trinidad) and took many of its supplies. The expedition later continued its journey west and reached the island of Homonhon in the eastern Philippines on 16 March, with only 150 crewmen. There they were able to communicate with the local peoples because the Malayan interpreter, Enrique of Malacca, could understand their language. The expedition took them further into the archipelago to the Visayan island of Cebu, where Magellan's chaplain, Pedro Valderrama, baptised the local monarch Rajah Humabon, his chief consort, and his subjects.