It now became apparent to Lee that he must hold an inner line west of Petersburg until nightfall, when it would be possible for him to retreat from the city. While gray-clad troops were forming along this line built on the banks of Old Indian Town Creek, the defenders of Fort Gregg put up a stubborn delaying action against the Northern advance. Approximately 300 men and two pieces of artillery met an onslaught of 5,000 Northerners. The outcome of the struggle was determined by the numbers in the attacking force, but the capture of Fort Gregg occurred only after bitter hand-to-hand combat. The purpose of the defense had been accomplished, however, for a thin but sturdy line running behind them from Battery 45 to the Appomattox River had been manned. Temporarily, at least, street fighting within Petersburg had been avoided. Blows directed at other points, such as Fort Mahone on the Jerusalem Plank Road, were slowed after troops of Maj. Gen. John G. Parke’s IX Corps had captured 12 guns and 400 yards of the Confederate line to the right and left of the road. Desperate counterattacks by Gordon’s Confederates kept the Federals from exploiting this breakthrough. Yet there was no doubt in the minds of Lee and other Southern leaders that all hope of retaining Petersburg and Richmond was gone. It was obvious that, if the lines held the Union army in check on April 2, they must be surrendered on the morrow. The object was to delay until evening, when retreat would be possible. The close of the day found the weary Confederates concentrating within Petersburg and making all possible plans to withdraw. Lee had issued the necessary instructions at 5 o’clock that afternoon. By 8 p.m. the retreat was under way, the artillery preceding the infantry across the Appomattox River. Amelia Court House, 40 miles to the west, was designated as the assembly point for the troops from Petersburg and Richmond. Grant had ordered the assault on Petersburg to be renewed early on April 3. It was discovered at 3 a.m. that the Southern earthworks had been abandoned; an attack was not necessary. Union troops took possession of the city shortly after 4 o’clock in the morning. Richmond officially surrendered 4 hours later. President Lincoln, who had been in the vicinity of Petersburg for more than a week, came from army headquarters at City Point that same day for a brief visit with Grant. They talked quietly on the porch of a private house for 1½ hours before the President returned to City Point. Grant, with all of his army, except the detachments necessary to police Petersburg and Richmond and to protect City Point, set out in pursuit of Lee. He left Maj. Gen. George L. Hartsuff in command at Petersburg.