Question: What is the abbreviation of the military entity the Saint Patrick's Battalion fought as?
Sentence (from "Saint Patrick's Battalion"): The Saint Patrick's Battalion (Spanish: "Batallón de San Patricio" ), formed and led by John Riley, was a unit of 175 to several hundred immigrants (accounts vary) and expatriates of European descent who fought as part of the Mexican Army against the United States in the Mexican–American War of 1846–8.
Relevant evidence: Yes