置之度外 — “To disregard personal gains, losses, safety, or life and death”

Towards the end of the Western Han Dynasty, Liu Xiu raised an army, defeated Wang Mang's Xin Dynasty, and then suppressed and incorporated various peasant uprising armies across Hebei and Shandong. He established the Eastern Han Dynasty in Luoyang, becoming its first emperor (Emperor Guangwu).

In the early years of the Eastern Han, the country was not fully unified. Many local factions held sway over different regions, resisting the new empire, while others, though nominally submissive, secretly maintained their territories. Powerful peasant armies also remained active. Liu Xiu spent over five years to achieve a foundational unity, with only two major warlords remaining: Wei Xiao in Gansu and Gongsun Shu in Sichuan. Wei Xiao had outwardly pledged allegiance to Liu Xiu, even sending his son to serve as an official in Luoyang as a sign of submission. Gongsun Shu, however, proclaimed himself King of Shu, commanding hundreds of thousands of troops and occupying the mountainous terrain of Sichuan. Due to logistical difficulties and the continuous years of warfare his troops had endured, Liu Xiu initially decided against immediate campaigns against these two, preferring to allow his forces to recuperate.

According to the 'Book of the Later Han: Biography of Wei Xiao', Liu Xiu once told his generals, '且当置此两子于度外耳！' (For now, let's put these two fellows out of consideration for a while!) Later, Liu Xiu eventually launched military campaigns, first defeating Wei Xiao, and then conquering Gongsun Shu's independent kingdom. This statement by Liu Xiu, as recorded in the 'Book of the Later Han', is the origin of the idiom '置之度外'.