The first shots fired at Fort Sumter in April 1861 signaled the start of the American Civil War and the end of compromise between the North and the South. A divided nation would now settle their differences over the issues of slavery and states' rights on fields of battle. From May to June 1864, in the fourth year of the Civil War, the armies under General Grant and General Lee had fought across Virginia from near Fredericksburg to just outside Richmond. The last battle of this campaign was a crushing Union loss and forced Grant to abandon his plan to capture Richmond by direct assault. Only twenty-five miles south of Richmond, Petersburg was an important supply center to the Confederate capital. With its five railroad lines and key roads, the city of Petersburg became the setting for the longest siege of the Civil War when Grant's army settled in to subdue the Confederacy by cutting off Lee's supply lines.