Quid pro quo. I'm sure it was not explicit. After all, one of the participants was already dead. However, if it quids like a pro and quos like a pro, it surely smacks of mutual benefit.
Columba was, like so many other Christian girls during the Roman Empire, sentenced to martyrdom for her faith. A jailer tried to rape her, but a nearby bear (no doubt one that would later kill Christians in the arena) attacked and killed the offending guard. Kind, but it did not spare Columba her beheading.
Almost immediately after her execution, a blind man prayed for her intercession with God so that his sight might be restored. It was, and with his restored vision, he immediately set about giving her body a decent burial and testifying on her behalf. A chapel was built upon her grave and Columba the Headless Virgin became St. Columba of Sens.