John Thomond O'Brien

John Thomond O'Brien (1786–1861), also known in Spanish as Juan Thomond O'Brien, was an Argentine Army officer born in 1786 in Baltinglass, Co. Wicklow, son of Martin O'Brien and Honoria O'Connor. He fought in the Chilean War of Independence.

Career
John Thomond O'Brien left Ireland and arrived in Buenos Aires in 1812 to open a merchant house. On his way there, his ship crashed onto the rocks of Fernando Po Island in west Africa. Only he and a few others survived to continue their journey.

Soon after arriving in Buenos Aires, the local people gave him the name Don Juan O'Brien. He enlisted in the army and fought in Uruguay with General Miguel Estanislao Soler. In 1816 O'Brien joined General José de San Martín's mounted grenadiers regiment in the Andes army. After the battle of Chacabuco, he was promoted to captain and appointed aide-de-camp to General San Martín.

O'Brien fought in the Second Battle of Cancha Rayada and at Battle of Maipú. In 1821 he was promoted to Colonel, and died in 1861 in Lisbon, Portugal while returning to South America.

Honours
In 1938 John (Juan) Thomond O'Brien's remains were sent back to Argentina where he received an official funeral. A town was also named after him, as was the Chilean Oberon class submarine O'Brien.