[3][5] In the mid-1560s, as the Spanish Empire expanded northward from the Caribbean to unexplored Florida, it founded the colony of St. Augustine, which has become the oldest continuously occupied European settlement on the United States mainland.

During the first half of the 18th century, priests held Mass in St. Augustine's hospital, which became too small for the congregation and embarrassed it before the Native American converts to Catholicism.

Spanish mission features include curving bell gables, limited fenestration, clay roof tiles, a semicircular tympanum, prominent statuary niche, and comparatively unadorned walls.

Neoclassical details surround the entry door; an entablature embellished with triglyphs topped with a broken pediment above and supported by pairs of Doric columns below.

[7] On April 12, 1887, with Florida, a part of the United States, the old Spanish structure burned once again, but the coquina blocks and cement masonry of the exterior were still salvageable.

The congregation hired the visiting New York City architect James Renwick Jr.,[8] who rebuilt and enlarged the church with a rectangular-cruciform layout and a European-style transept.