Siena, Siena Province, Tuscany, Italy. Il Museo dell'Opera del Duomo. Cathedral Museum. A thirty square meter stained glass masterpiece created by Sienese artist Duccio di Boninsegna (1260-1318). It was created in 1287-1288 and was originally in the apse of the cathedral. It is considered one of the triumphs of Sienese art.