Diego Luis de San Vitores was born on November 12, 1627 at Burgos to a noble Castilian family. At the age of 13, Diego entered the Society of Jesus at Madrid.
In 1660, Diego sailed for the Philippines as Jesuit missionary. During his journey he passed through the Mariana Islands (then known as the 'Ladrones Islands' — 'Islands of Thieves', the name given by Magellan in 1521) — receiving the vocational call to the Christianization of the Chamorro indigenous people.
In 1668, after 8 years of diplomatic effort with the Spanish crown (specifically with Queen Regent Mariana of Austria), Diego received royal authorization to establish the Mariana mission. The islands were renamed the 'Mariana Islands' in honor of Queen Mariana.
Diego and four Jesuit companions landed on Guam on June 15, 1668 — establishing the Catholic mission in the Mariana Islands. For the 4 years (1668–1672), Diego travelled across the Mariana Islands (Guam, Rota, Tinian, Saipan) baptizing thousands of Chamorros.
The Chamorro traditional resistance to the Catholic and Spanish colonial influence produced sporadic violence.
On April 2, 1672, at Tumon Bay on Guam, Diego baptized the infant daughter of the Chamorro chief Matapang against Matapang's will. Matapang and his companion Hurao killed Diego with spears and cutlasses.
Diego's body was thrown into the sea and never recovered. Beatified October 6, 1985 by Pope St. John Paul II.