Which dynasty did Mulan join the army?

Why did the poem "Mulan Shi" appear in the Yuefu Poetry of the Han Dynasty established during the reign of Emperor Wu of the Han Dynasty? If it was about the Northern Dynasty, it wouldn't have been widely spread in the Han Dynasty?
Shouldn't the emperor at that time be called 'Khan'?

Answer 1

Mulan joining the army was an allusion that appeared in Chinese history. It usually appeared in the Ode of Mulan. "Ode to Mulan" was an ancient poem with Mulan as the main character. It described the story of a heroine, Hua Mulan, who fought for her father on the battlefield and finally won.

The story of Mulan joining the army could be traced back to the Northern and Southern Dynasties. It was said that the Emperor of the Northern Wei Dynasty wanted to recruit a group of brave women to join the army so that they could play an advantage in foreign wars. Hua Mulan was one of the women who was recruited. Her father was recruited to be an official in Northern Wei. Hua Mulan decided to replace her father in the battle and finally won.

The story of Mulan joining the army was deeply loved by the people. Not only was it widely circulated in ancient times, but it was also adapted into various literary works such as "Ode to Mulan" and television dramas, becoming a much-told story in Chinese culture.