Qeybtaan sii wad - bartamihii qarnigii 19aad, tiro badan oo muhaajiriin Irish ah ayaa lagu soo qaatay guutooyin Irish ah oo ka tirsan Ciidanka Mareykanka waqtigii Dagaalkii Mexico iyo Mareykanka. Inta badan 4,811 askari oo Irish ah ayaa ka soo shaqeeyay Ciidanka Mareykanka, laakiin qaar ayaa u cararay Ciidanka Mexico, ugu horreyn si ay uga baxsadaan dhibaatada saraakiisha Protestant iyo takoorka adag ee ka dhanka ah Katooliga ee Ameerika. Kuwani waxay ahaayeen "San Patricios", ama Saint Patrick's Battalion - koox Irish ah oo uu hogaaminayo John O'Riley oo ku dhashay Galway, oo ay weheliyaan qaar Jarmal ah, Scottish iyo American Catholics. Waxay ku dagaalameen ilaa ay ka dhiibeen dagaalkii xasaasiga ahaa ee Churubusco
, waxaana lagu fuliyay meel ka baxsan Magaalada Mexico dowladda Mareykanka 13kii Sebtember 1847. Guutada waxaa lagu xusaa Mexico sanad walba 12-ka Sebtember.