Both men subsequently joined the Mexican Army, where they eventually formed the Batallón de San Patricio, or Saint Patrick's Battalion.

The battalion itself was formally disbanded in August 1848, six months after the end of the war, allegedly due to one of the unit's officers being implicated in an attempted military coup.

[clarification needed] While he escaped the mass hanging of around 50 other captured members of the Saint Patrick's Battalion, Riley was branded on his cheek with the letter "D" for deserter.

It reads: In the H. [Heroic] city of Veracruz, on the thirty first of August of eighteen hundred and fifty, I, Don Ignacio Jose Jimenez, curate of the parish church of the Assumption of Our Lady, buried in the general cemetery the body of Juan Reley, of forty five years of age, a native of Ireland, unmarried, parents unknown; died as a result of drunkenness, without sacraments, and I signed it.

Some arguments[6] which cast doubt on Miller's original presumption include: Research conducted in September 2012 in Clifden, County Galway failed to turn up any John Riley who would fit into the age described on the death certificate.

[citation needed] In his honour, and to commemorate Saint Patrick's Battalion, a bronze sculpture was erected in his birthplace of Clifden, Ireland, as a gift from the Mexican government.