19th Century: Wars and Abandonment
In 1811, the fortress was occupied by patriot forces, but shortly afterward it was invaded by Portuguese troops. This period coincided with the events that led to the Eastern Exodus
Between 1825 and 1828, during the Liberating Crusade, Colonel Leonardo Olivera carried out significant actions against the Brazilian Empire’s forces in the region.
During the administrations of Rivera and Oribe (1830–1843), Santa Teresa functioned as a frontier watchpoint, monitoring military movements.
In 1895, the fortress was used as a prison, further deteriorating its structures.
By the end of the 19th century, it was virtually abandoned, with its stones being looted and advancing sand dunes threatening to bury the structure.