At the time people followed biblical laws which dictated women's clothing.

It was decided at the nullification trial that Joan was within her rights to wear men's clothing during a journey and on a battlefield.

They beleived it was a crime against god, if you've heard her story and know she was burned for witchcraft and heresy. Heresy is going agaisnt the king, by dressing in mens clothing and attacking it. Joan of Arcadia even insisted on wearing men's clothing when she was locked up and going through her trials. For two reasons: One her voices hadnt told her to stop wearing men's clothing and Two, to aviod sexual abuse from her jailors.