 In early December, Quay was forced to resign due to his disease and O'Brien was promoted to colonel, Thompson to lieutenant colonel, and Captain William H. Shaw to major.The 134th fought in the Battle of Fredericksburg on December 13, losing 14 killed, 106 wounded, and 19 missing.Despite his illness, Quay volunteered to serve as an aide to General Tyler throughout the battle, for which he would receive a Medal of Honor in 1888.