Annam was a kingdom in OTL North Vietnam that was founded in 968 and existed until 1780.
In 1310, the Vietnamese king Tran Anh Tong defeated Champa and made it a vassal. But when Annam became a tributary of Hong China in 1376 (3073, Yang Fire Dragon), Champa threw off Annam's influence. 1385 however, Hong China and Annam made Champa a tributary again.
1425/26: Hong China invaded Annam and makes the kingdom a vassal
Late 1480s: A great Vietnamese rebellion against Chinese rule occurs in Annam. The Chinese struggle to put down the uprising but eventually the rebellion was defeated and Annam was annexed and becomes a Chinese province.
1673: Annam gains independence from Hong China in a successful revolt.
1780s: Champa annexed Annam, ending the kingdom.