Halleck arrived from St. Louis on April 11, took command, and assembled a combined army of about 120,000 men. On April 29, he relieved Grant of field command and replaced him with Major General George Henry Thomas. Halleck slowly marched his army to take Corinth, entrenching each night. Meanwhile, Beauregard pretended to be reinforcing, sent "deserters" to the Union Army with that story, and moved his army out during the night, to Halleck's surprise when he finally arrived at Corinth on May 30.