Battallon de San Patricio

Battallon de San Patricio, Guanajuato, Mexico

With the U.S. annexation of Texas in 1846, tensions with Mexico had reached a critical point. At the same time, many Irish Catholics were immigrating to America in the wake of famine and unrest in Ireland.

In the Army, as with the rest of the country, the Irish Catholics faced discrimination, and were often given dirty, lowly jobs.

Mexican generals learned of the plight of the Irish soldiers and took advantage of it — offering land, money, and potential for advancement for any soldier who deserted and joined them. The prospect of defecting to fight for Mexico meant better conditions overall. Unlike the U.S. Army, the Mexican Army treated the Irish like heroes.

Originally, the immigrants were assigned to the “legion of foreigners” under the Mexican Army. After the Battle of Resaca de la Palma — one of the earliest battles of the Mexican-American War — the legion was organized into the St. Patrick’s Battalion.