The ARVN committed almost all their remaining mobile forces, especially the 18th Division, under Brigadier general Lê Minh Đảo, to the defence of the strategic crossroads town of Xuân Lộc, hoping to stall the PAVN advance. The battle was fought between 9 and 21 April 1975, and ended when the town of Xuân Lộc was captured by the PAVN 4th Army Corps led by Major general Hoàng Cầm. This was the ARVN III Corps' last defensive line east of South Vietnam's capital, Saigon. The line connected the city of Bình Dương, Bien Hoa Air Base, Vũng Tàu, Long An and the lynchpin centered on the strategic town of Xuân Lộc, where the South Vietnamese Joint General Staff committed the nation's final reserve forces in Saigon's defense. In the last-ditch effort to save South Vietnam, Thiệu ordered the 18th Infantry Division to hold Xuân Lộc at all costs. The PAVN 4th Army Corps, on the other hand, was ordered to capture Xuân Lộc in order to open the gateway to Saigon. During the initial stages of the battle, the 18th Division managed to beat off early attempts by the PAVN to capture the town, forcing PAVN commanders to change their battle plan. However, on 19 April 1975, Đảo's forces were ordered to withdraw after Xuân Lộc was almost completely isolated, with all remaining units badly mauled. This defeat also marked the end of Thiệu's political career, as he resigned on 21 April 1975.