The medieval era was one of great religious beliefs and witchcraft. Because of this, it heavily reflected on the styles worn by women and even men back in those days. Braids were hugely popular and were often worn in the back of the head. If the head was covered, which it often was, hair was merely peeking out from the sides of the headdress.
Medieval hairstyles were a display of wealth and high status females normally wore their hair long and curly. Medieval hair styles are still fairly popular in this day and age for weddings and other special events.