 Complete the following phrase:  In September 1863, the Union army in Tennessee was defeated at the Battle of Chickamauga and two corps were sent west to help them as they were besieged in Chattanoogathe XI and XII Corps. They later were combined due to their small sizes into a new XX Corps, Army of the Cumberland. Williams division did not reach Chattanooga, but guarded railroads in eastern Tennessee. However, it did join Maj. Gen. William T. Sherman as part of XX Corps in the Atlanta Campaign and fought with distinction in a number of battles, particularly the Battle of Resaca. Williams was wounded in the arm at the 