This intimate oratory has a dramatic ceiling painting of the Assumption by Giambattista Tiepolo, with a glowing Madonna framed by tumbling, rather mischievous looking cherubs. It's a wondrous work. Eight biblical scenes in far more sombre chiaroscuro on the walls are by his son, Giandomenico. The building opened as a theatre in 1680 but the patriarch of Aquileia ordered its transformation 80 years later, repulsed that such a devilish institution existed so close to a cathedral.