At last, on March 29th, 1865, Grant pushed forward 50,000 cavalry and infantry to execute the very move which Lee had outlined and for which he was as thoroughly prepared as it was possible to be with the men he had on hand. But to check this advance which threatened to surround his army and cut off his retreat, he had to withdraw the troops guarding the defenses of Petersburg, abandoning some of the intrenchments altogether and leaving nothing much more formidable than a skirmish line anywhere along his front. Even then he could not stop the onrush of the Union troops, which, under Sheridan, circled his right on April 1st and drove back his men in the fierce engagement known as the battle of Five Forks. With the news of this success Grant promptly ordered an assault against the intrenchments and his troops tore through the almost defenseless lines in several places, encountering little or no resistance.
Petersburg was not yet taken, but Lee immediately saw that to protect it further would be to sacrifice his entire army. He, therefore, sent a dispatch to Richmond, advising the immediate evacuation of the city. "I see no prospect of doing more than hold our position here till night. I am not certain that I can do that," he wrote. But he did hold on till the Confederate authorities had made their escape, and then on the night of April 2nd he abandoned the capital which he had successfully defended for four years and started on a hazardous retreat.
The one chance of saving his army lay in reaching the mountains to the west, before Grant could bar the road, but his men were in no condition for swift marching and the provision train which he had ordered to meet him at Amelia Court House failed to put in an appearance, necessitating a halt. Every moment was precious and the delay was exasperating, but he did his best to provide some sort of food for his famished men and again sent them on their way.
By this time, however, the Union troops were hot upon their trail and soon their rear-guard was fighting desperately to hold the pursuit in check. Now and again they shook themselves free, but the moment they paused for food or rest they were overtaken and the running fight went on. Then, little by little, the pursuing columns began to creep past the crumbling rear-guard; cavalry pounced on the foragers searching the countryside for food and captured the lumbering provision-wagons and the railroad supply trains which had been ordered to meet the fleeting army, while hundreds upon hundreds of starving men dropped from the ranks as they neared the bypaths leading to their homes.