During much of the 3rd century, the three empires of Wei, Shu and Wu existed on the territory of modern China. Only Wei managed to survive over a longer period of time. The epoch from about 200 to 280 is therefore known as the "period of the three empires" in China. Naturally the three empires minted their own coins. This piece was issued by the house of Wu in the year 236 AD. That year, a law stipulated the exchange of the entire money supply into such new coins. The legend reads "ta-ch'üan wu-pai" – "big coin with a value fo 500."