Colonial roots
The saint's name was present in Santo Domingo from early on. Colonial genealogies of the capital's families use "Tomás de Aquino" as a given name.2 As a surname, Aquino appears among the established families of the capital. A genealogy of Santo Domingo families records Aquino Amador, born in 1807, son of Bruno Aquino Montes de Oca and Vicenta Amador Hevia.3
In the Cibao, the 1812 census (padrón) of San Francisco de Macorís, which covered 1,816 people under 334 household heads, lists Pedro Aquino, aged 30, and Francisca Aquino, aged 20, in the Partido de las Guásumas. The same census records a child named Tomás de Aquino in Mirabel.4 This matters for the Serie 59 story, because Castillo was part of the Macorís jurisdiction until the late 19th century.5
Why the branches are unrelated
Two separate processes, repeated in different places, produced Dominican Aquinos:
- Colonial Spanish and Canarian families that already carried the surname.3
- Devotional naming after Saint Thomas Aquinas, where "de Aquino" passed from a baptismal name to a surname.64
Each process could happen in more than one place, so the same surname arose independently in different regions. Genealogists treat regional clusters as separate branches until documents prove a link.