Guam

Guam is the largest island of the Mariana Islands in the Pacific Ocean, which include Saipan and Tinian of World War II fame. It is located roughly 1,500 miles (1 mile = 1.609 kilometers) east of the Philippines. Presently, it is a U.S. territory, and as such there is a substantial U.S. military presence on the island. The United States is one of three foreign powers, along with Spain and, briefly Japan, to occupy Guam. Roman Catholicism is the dominant religion of the indigenous Chamorro population. This is due to nearly 300 years of Spanish contact, missionization, and colonialism. Native-born Protestants make up a small minority, and there are still those who practice the traditional Chamorro religion.

The first European to set foot on the island was the Portuguese explorer Ferdinand Magellan in 1521. The explorer, sailing for Spain, claimed the archipelago for the Spanish Crown. He named the islands the Islands of the Thieves due to his experience with the indigenous population. Magellan's stay was short. After the explorer's departure, European contact was infrequent. It was not until the establishment of the Spanish colony in the Philippine Islands in the 1560s that Spanish ships, primarily galleons, stopped at Guam at regular intervals. Although Spain had long claimed Guam and the other islands, there had been no systematic effort to either convert the indigenous population to Catholicism or establish a permanent colony.

This changed in 1662. Father Diego Luís de San Vitores of the Society of Jesus briefly arrived in Guam while en route to the Philippine Islands. He believed that the indigenous population of the island chain was ripe for conversion. While in the Philippines, he agitated for funds and permission to lead a mission to the islands. After a few setbacks, the Guam mission was authorized by the Queen Regent of Spain, Mariana of Austria. In 1668, Father San Vitores founded the first mission and renamed the Islands of the Thieves as Mariana Islands, in honor of Queen Mariana. Initially, Father San Vitores's conversion efforts were peaceful, but within a short time war broke out between the Chamorros and the Spanish soldiers sent to protect the missionaries, eventually costing the ambitious priest his life. The Chamorros were eventually subdued by force, and Catholicism was forced on the population. Roman Catholicism maintained a monopoly on religion in the Mariana Islands until the end of Spanish colonial rule in 1898.

With the U.S. victory in the Spanish-American War, Guam became a U.S. territory to be governed by the Department of the Navy. Prior to its surrender, Spain ceded the other islands to Germany. The arrival of U.S. naval rule ushered in a new era of missionary activity. Missionaries attempted to convert the Chamorros from Catholicism to Protestantism. For the most part, they failed. This occurred for two reasons. First, Spanish Catholicism had long been established, and second, the Protestant missionaries were poorly funded. Thus, Catholicism has maintained its dominant position in Guam.