• To protect herself from unsolicited sexual advances.
• It was more suitable for battle
Explanation:
This relates to Joan of Arc who was tried and convicted of cross-dressing and burnt at the stake after being captured by pro-English forces in the Hundred Years War.
One reason she dressed as a man would may have been because she did not want to be approached by the men she was surrounded by as she was mostly surrounded by men from the time she led French forces to the time she was in prison.
She wanted her chastity protected and reasoned that if the men thought of her as less of a woman, they wouldn't approach or force themselves on her.
Another reason may have been the mobility provided by men's clothing in battle. Joan led the French armies in a number of battles and so needed to be mobile and men's clothing gave her that mobility.
