Santísima Trinidad or Most Holy Trinity was a fortress in the

Captaincy General of Chile The Captaincy General of Chile (''Capitanía General de Chile'' ) or Governorate of Chile (known colloquially and unofficially as the Kingdom of Chile), was a territory of the Spanish Empire from 1541 to 1817 that was, for most of its existenc ...

that existed on the north shore of the Bio-Bio River in what is now the Bío Bío Province. It was built directly across the river from Fort Espíritu Santo by the

Royal Governor of Chile The Royal Governor of Chile ruled over the Spanish colonial administrative district called the Captaincy General of Chile, and as a result the Royal Governor also held the title of a Captain General. There were 66 such governors or captains du ...

Alonso de Sotomayor Alonso de Sotomayor y Valmediano (; 1545–1610) was a Spanish conquistador from Extremadura, and a Royal Governor of Chile. Early life He was born in Trujillo, in the province of Extremadura, the son of Gutiérrez de Sotomayor e Hinojosa a ...

in 1585. It was abandoned by the same governor in 1591 and destroyed by the Indians in the great rising of the

Mapuche The Mapuche ( (Mapuche & Spanish: )) are a group of indigenous inhabitants of south-central Chile and southwestern Argentina, including parts of Patagonia. The collective term refers to a wide-ranging ethnicity composed of various groups who sha ...

that followed the death of Governor

Martín García Óñez de Loyola Don Martín García Óñez de Loyola (1549 in Azpeitia, Gipuzkoa – December 24, 1598 at Curalaba) was a Spanish Basque soldier and Royal Governor of the Captaincy General of Chile. Very likely Ignatius of Loyola, the founder of the Society of ...

. It was constructed again in 1603 by Governor

Alonso de Ribera Alonso de Ribera y Zambrano (; 1560 – March 9, 1617) was a Spanish soldier and twice Spanish royal governor of Chile (1601–1605 and 1612–1617). Early life Born in Úbeda, he was the illegitimate son of Hidalgo and Captain Jorge de Ribera Za ...

but it disappeared few years later.

Sources

Francisco Solano Asta-Buruaga y Cienfuegos, Diccionario geográfico de la República de Chile, D. Appleton y Compania, Nueva York, 1899
pg.842 Arauco War Buildings and structures in Biobío Region Colonial fortifications in Chile {{Chile-struct-stub