This is saint Agnes. At 12, she was outed as a Christian. So, because the Roman authorities were horrible to women who hoped to remain virtuous for Christ, they sentenced her to be stripped nake-y and put on display in a well-trafficed location. The down side for any leering pervs, however, was that they were struck blind for looking at her. I guess enough dudes went blind that they decided to just end it and beheaded her.
To have a reminder of virtue in the house (especially near the computer!), click here.