According to popular legend, the Chinese governor Su Ting ordered the assassination of Trung Trac's husband, Thi Sach, one of the leaders of the anti-Chinese uprising. Because of this loss, Thi Sach's wife and her sister took up the cause themselves in 40AD. In a seventeeth-century poem, Trung Trac declares to her 80,000 troops:
Foremost, I will avenge my country,
Second, I will restore the Hung lineage,
Third, I will avenge the death of my husband,
Lastly, I vow that these goals will be accomplished.
The war was a success, and the sisters seized control of 65 citadels and declared themselves queens. They abolished unfair taxes and the country enjoyed a period of calm. The Chinese retaliated with overwhelming force in 43 AD, however, and the sisters, rather than face defeat, drowned themselves in the Hat Giang River. Although they ultimately failed in ridding Vietnam of its oppressors, the Trung Sisters lived on in legend, inspiring pride and confidence during the many anti-colonial uprisings in the centuries that have followed.
Other scholarly investigations suggest that Trung Trac and her sister were quite capable and determined to lead a war, and that later, more patriarchal traditions necessitated the chapter involving Thi Sach's assassination, and therefore his wife's "need" to avenge his death. It is possible in fact that Thi Sach actually did not die in this exact manner, but lived to follow the martial leadership of his wife. Ancient Chinese records also preserve the biographies and names of the officers in the uprising, many of whom were women (including the Trungs' own mother). The Trung sisters, though often said to have drowned themselves (or "they disappeared into the clouds," or "they became ill and died"), more likely were beheaded by their enemies.
Sources:
viettouch.com, article "Trung Trac and Trung Nhi" by Tuyet A. Tran & Chu V. Nguyen
womeninworldhistory.com (Bios: The Trung Sisters) "The Birth of Vietnam" by Keith Weller Taylor