What was the first recorded large-scale migration from southern Sichuan?

Waiter. The Liao people who entered Sichuan from the south brought advanced agricultural technology and culture, which had a far-reaching impact on Sichuan's economic, cultural and social development. This migration activity not only increased the population of Sichuan, but also promoted the exchange and integration between Sichuan and the south, and promoted cultural diversity and social progress.