In 214 BC, Qin Shi Huang secured his boundaries to the north with a fraction of his large army (300,000 men), and sent the majority (500,000 men) south to seize still more land. At that time, southern China was known for its fertile land, elephant tusks and jade production. Prior to the events leading to Qin dominance over China, the Baiyue had gained possession of much of Sichuan to the southwest. The Qin army was unfamiliar with the jungle terrain, and was defeated by the southern tribes' guerrilla warfare tactics, with over 100,000 men lost.
However, Qin did manage to construct the Lingqu Canal to the south, which they used heavily to supply and reinforce their troops during a second attack to the south. Building on these gains, the Qin armies conquered the coastal lands surrounding Guangzhou and took areas of Fuzhou and Guilin. After these victories in the south, the First Emperor moved over 100,000 prisoners and exiles to the newly conquered area to colonize them.
By 208 BC, Zhao Tuo had reached Cổ Loa Citadel, capital of the state of Âu Lạc, 16 km (10 mi) northeast of present-day central Hanoi. Then, he defeated An Dương Vương and founded Nanyue kingdom in the same year.