Spanish colonization commenced on June 15, 1668 with the arrival of Diego Luis de San Vitores and Pedro Calungsod, who established the first Catholic church.:64 The islands were part of the Spanish East Indies governed from the Philippines, which were in turn part of the Viceroyalty of New Spain based in Mexico City. Other reminders of colonial times include the old Governor's Palace in Plaza de Espana and the Spanish Bridge, both in Hagatna. Guam's Cathedral Dulce Nombre de Maria was formally opened on February 2, 1669, as was the Royal College of San Juan de Letran.:68 Guam, along with the rest of the Mariana and Caroline Islands, were treated as part of Spain's colony in the Philippines. While Guam's Chamorro culture has indigenous roots, the cultures of both Guam and the Northern Marianas have many similarities with Spanish and Mexican culture due to three centuries of Spanish rule.
Is there an answer to this question (If it cannot be answered, say "unanswerable"): On what date did Spain colonize the Philippines?
unanswerable