— After the Union's bruising defeat at Chickamauga, in the northwest corner of Georgia not far from Chattanooga, Ulysses S. Grant heads to take charge of federal troops hemmed in at Chattanooga now besieged by Confederate forces all around. This week 150 years ago in the Civil War, Grant arrived in that eastern Tennessee city on the front lines of war and immediately began the task of creating a secure federal supply line. His aim: to immediately re-arm and expand the hold of Union troops who had been precariously holding the city against Confederates on the surrounding mountain heights. This month 150 years ago, Grant formally took charge of tens of thousands of troops in a broad new Military Division of the Mississippi, his star rising in President Abraham Lincoln's eyes after a Grant victory in July at Vicksburg, Miss. In little more than a month's time, the pugnacious Grant would order an offensive to break a Confederate siege, knocking the secessionists from their positions overlooking Chattanooga from atop Missionary Ridge and other heights.