A beautiful young maiden who was so horrified at the thought that a man might fancy her that she prayed for ugliness.
Zap! Suddenly she was hideous. Her father took one look and packed her off to the first nunnery. She was of course delighted — even when God rewarded her piety by making her beautiful again.
Originally a very popular Celtic Goddess (see BRIGIT), she was ‘borrowed’ and given a new identity to promote the Christian Faith. Unless it’s a complete coincidence.