Boudicca or Boadicea was the queen of the Iceni - a celtic tribe - who lead a rebellion against the roman domination in A.D. 61.
The death of 70.000 romans and romanized brits gave freedom to her people for a while, until the romans regroup and reverse her victory.
She was described as tall, of a comely countenance and impressive attitude, wearing a loose gown, a golden chain around her neck and bore a spear.
The queen was not the only woman in the battlefield for among the celts the presence of female warriors were quite commom.
SALMONSON, Jessica Amanda. The Encyclopedia of Amazons: Women Warriors from Antiquity to the Modern Era. New York: Anchor Books, 1991, pp. 38-39.