Prominent among these were the victory of the _Monitor_ over the _Merrimac_, in Hampton Roads; the capture of Roanoke Island and Fort Pulaski; Grant's gallant victories at Forts Henry and Donelson, at Island No. 10, and, later, at Pittsburg Landing; and the heroic taking of New Orleans by Farragut and Butler. [Sidenote: Chancellorsville.] At the very threshold of the third year of the war, President Lincoln issued the "Proclamation of Emancipation." Thus not only was the crime of slavery wiped away, but a new source of strength to our forces was provided by the emancipated negroes, who were enlisted to aid in the confirmation of their freedom by final victory. The first half of the year 1863 witnessed what was perhaps the gloomiest and most disheartening period of the war. Hooker succeeded Burnside, only to meet at Chancellorsville the same disastrous fate which had overtaken his predecessor at Fredericksburg. General Lee was encouraged to assume the offensive, and to invade Pennsylvania. The North was discouraged; the expense of the war began to be grievously felt; the draft was becoming very obnoxious; the desertions from the army were alarming in number. [Sidenote: Gettysburg.] Lee advanced by the Shenandoah Valley into the Northern States. But at Gettysburg he met the reorganized Union army, under Meade. The collision of one hundred and sixty thousand men, lasting for three days, resulted in that hard-won Union victory which proved the turning-point of the war. On the day of Lee's retreat from Gettysburg, the Fourth of July, Vicksburg was surrendered to Grant. Soon after, Port Hudson fell, and the Mississippi was opened to the passage of troops. Then the Battle of Chattanooga was fought and won, and Tennessee was rid of Confederate occupation. Meanwhile, the siege of Charleston was proceeding on the coast, and before the end of the year Fort Wagner was taken. [Sidenote: Grant Commander-in-chief.] [Sidenote: Sherman's March to the Sea.]