On the evening of August 29, General Robert E. Lee arrived with General James Longstreet and the remainder of the Confederate Army of Northern Virginia. Longstreet placed his men in a position to launch a surprise attack against the left flank of the Union army the following day. On the morning of August 30, Pope resumed his attack on Jackson’s lines. At one point, Southern soldiers running low on ammunition resorted to hurling rocks at their enemies to drive them back. With the Northerners unaware of his presence on their left, Longstreet ordered his men forward. His troops quickly annihilated a unit of colorfully uniformed New York Zouaves that stood in their path. Pope desperately sent the few troops available to slow the Confederate assault and buy time for the Union army to form a new defensive line on Henry House Hill. The Yankee army had been badly beaten, but not destroyed.