The Van Dyck painting that hung in Scotland’s National Gallery for more than 100 years, was keeping a secret. “After a year of restoration and investigation, staff at the Edinburgh gallery have been able to shed light on a work Van Dyck wanted no one to see. Underneath the canvas of St Sebastian Bound for Martyrdom is a previous work, also of St Sebastian and almost an exact copy of a Van Dyck that hangs in the Louvre.”