The history of Hagatna, the administrative centre of Guam, dates back to ancient times. This location was one of the significant settlements of the indigenous Chamorro people, who arrived here, according to various estimates, around 500 AD. The city's current name comes from the Chamorro word "haga", meaning "blood", serving as a reminder of the ancestral bloodlines that formed the foundation of ancient society.
The modern history of the city began in the 17th century with the arrival of the Spanish. In 1668, the missionary Diego Luis de San Vitores established the island's first Catholic mission here, marking the beginning of the transformation of the ancient village into the colonial city of Agana—the old name for Hagatna. It was from here that the Spanish colonisation of the Mariana Islands commenced, and the city quickly became the administrative and religious hub of Spanish possessions in the region.
Several factors contributed to Hagatna becoming the capital. Firstly, its strategic location on the west coast of the island, within a convenient bay, made the city a vital point for Spanish ships in the Pacific Ocean. Secondly, by becoming the residence of the Spanish governor, Hagatna concentrated all administrative and military power on the island. Furthermore, the Spanish administration implemented a policy of centralising the population, relocating the indigenous Chamorro people to controlled centres, one of which was Hagatna, facilitating governance and the spread of Christianity.
During the Spanish period, the culture of Hagatna represented a blend of Chamorro traditions and European influence. Catholicism became an integral part of life, reflected in the construction of churches, the most prominent being the Dulce Nombre de Maria Cathedral-Basilica. The city's economy was closely tied to its administrative status and the servicing of Spanish garrisons and fleets. Although Guam served as a stopover for Spanish galleons travelling from Mexico to the Philippines, its economic role was largely auxiliary, focused on replenishing supplies of provisions and fresh water.