Timewatch (BBC2, 9pm); Tonight's TV.
THIS documentary is called The Private Life of a Masterpiece.
Although not, strictly speaking, an Easter edition, it does focus on a particularly baffling event which took place during the Crusades.
Writer and historian Thomas Asbridge has been puzzled by what went wrong for a garrison of supposedly elite Knights Templar troops who were massacred at a castle by the River Jordan in northern Israel.
Construction began on the fort in 1179, and quickly its reputation spread, with experts claiming it was impregnable. It wasn't.