The town of Aparri, situated at the mouth of the Cagayan River, developed early as an important coastal settlement during the Spanish period, and it was within this setting that the Parish of San Pedro Telmo was formally established in 1680 under the Dominican missionaries.

Historical records show that the early church structures in Aparri were repeatedly affected by natural forces, particularly flooding, which at times led to the relocation of the church and settlement to more secure ground. The parish complex that eventually developed included a substantial church and convento built in the nineteenth century, along with a bell tower that underwent several reconstructions, including a major rebuilding completed and blessed in 1929. Remnants of earlier structures, such as brick walls and sections of the old cemetery enclosure, continue to reflect this long architectural history.

At the heart of the parish is the devotion to San Pedro Telmo, whose identity as patron of sailors resonates strongly with Aparri’s maritime character. Bells dedicated to the saint, some dating to the late nineteenth century, and traditional fluvial processions held in his honor demonstrate how deeply this devotion is rooted in the community’s religious life. The image of San Pedro Telmo, often depicted holding a miniature ship, reflects this enduring connection between faith and the sea.

Alongside this long-standing parish tradition is the devotion to Our Lady of the Rosary, which led to the designation of the church as an archdiocesan shrine in more recent times. This title commemorates an earlier Marian devotion associated with the Dominican mission in the area, highlighting the historical role of the Order of Preachers in promoting the Rosary in northern Luzon.