 Complete the following phrase:  Walker headed back to Arkansas in late 1863, but in March 1864, joined Taylor once again in Alexandria to help Taylor defend against the advances of Nathaniel P. Banks and his Army of the Gulf in the Red River Campaign. Walkers troops played a critical role in the Confederate victory at the Battle of Mansfield on April 8, 1864. Rather than leave Walkers Greyhounds with Taylor as he sought to capture the retreating Banks, Smith sent Walker north to fight Union General Frederick Steele. Walker engaged Steele at the 