In Mexico this past September, Irish-American Top 100 Honoree Bill O'Brien was guest of honor in the annual celebration of the Battal-n San Patricio, or Battalion of Saint Patrick (seen here with Ireland's Ambassador to Mexico, Dermot Brangan).

This group of soldiers, deserters from the United States Army, fought for the Mexican side in the Mexican-American War of 1846.

Regarded as traitors by some and heroes by others, the San Patricios were the subject of a feature article in the October/November 2008 issue of Irish America.

Mr. O'Brien, a former wool merchant, fluent Spanish-speaker and resident of Arizona, is a co-founder of the non-profit Irish Cultural Center in Phoenix in 1998, and is head of the San Patricio Society in his home state.