I was searching for some information in the Internet and I am not sure how, but the Trung Sisters turned up. Briefly, these ladies were responsible for the first successful revolt from the Han Chinese in 40 CE.
These two sisters successfully led the Vietnamese revolt against the Han Chinese and they were the military rulers of Vietnam for three years, until the Chin ese under Ma Yuan came and defeated them.
The sisters were born into a wealthy Lac family and were well educated. Trung Trac’s husband was Thi Sach and was the Lac lord of Chu Dien in northern Vietnam. Su Ding was the Chinese governor of Jiaozhi province at the time, remembered for his cruelty and tyranny. One thing led to another the result of which was Trung Trac and her younger sister Trung Nhi stirred the locals up into a rebellion to avenge the killing of her husband. It began in the Red River delta and then spread to other Lac areas and non-Han people from an area stretching from Hepu to Rinan. Chinese settlements were overran, and Su Ding fled. The uprising gained the support of about sixty-five towns and settlements. Trưng Trac was proclaimed as the queen.
In AD 42, the Han emperor commissioned general Ma Yuan to suppress the rebellion with 32,000 men. The rebellion of the two sisters was defeated in the next year as Ma Yuan captured and decapitated Trưng Trac and Trưng Nhi, then sent their head to the Han court in Luoyang.
There is a procession each year in celebration of the Trung Sisters and they are always depicted riding an elephant.
There is a good write up of this on Wikipedia, Trung Sisters