Hua Mulan was a legendary ancient Chinese warrior whose story was told in "The Ballad of Mulan". The story tells of a maiden disguising her female identity and joining the army to fight in battle so that her ill father and little brother wouldn't have to go.
The historical setting of Mulan is uncertain. Cheng Dachang of the Song Dynasty recorded that Mulan lived during the Sui and Tang Dynasties. Song Xianfeng of the Qing Dynasty (1644-1911 C.E.) believed that she was of Sui (581-618 C.E.) while contemporary Yao Ying believed that she was of the Five Dynasties (907-960 C.E.). Other sources say that Mulan lived before the Tang Dynasty (618-907 C.E.). Earliest accounts of the legend state that she lived duirng the Northern Wei Dynasty. This dynasty was founded by the Ximbei people 4th century and had suffered a wave of invasions from the Rouran Khaganate. This period in history matches with the scenarios described in the ballad, when Mulan fights against forces from the Mongolian/ nomadic tribes, which is the reason why the Northern Wei Dynasty is considered to be the right period when the story happened.
There's also disagreement about the heroine's name. While she is commonly refered to in Western culture as "Hua Mulan", different dynasty writers lay claim to her family name: Zhu (Ming), Wei (Qing), and in Cantonese: Fa. The name Mulan means "magnolia"; the words mu meaning "wood" and lan meaning "orchid". The name Hua means "flower".
The story was transcribed in the 6th century before the founding of the Tang Dynasty then compiled in the 11th or 12th century. The poem is a ballad meaning that the lines do not have an equal number of syllables. The story was expanded into a novel during the Ming Dynasty (1368-1644) and over time became popular with the Chinese public. It's also one of the first stories to deal with the issue of gender equality though Mulan is never discovered to be a woman in the story.
Mulan became known to western audiences in the summer of 1998 when Disney released a film adaptation of her story, simply called Mulan. In 1975 author Maxine Hong Kingston told her story in her book The Woman Warrior.