The Adoration of the Mystic Lamb, also called the Ghent Altarpiece (Dutch: De aanbidding van het Lam Gods),[A] is a large and complex 15th-century polyptych altarpiece in St Bavo's Cathedral, Ghent, Belgium. It was begun around the mid-1420s and completed by 1432, and it is attributed to the Early Netherlandish painters and brothers Hubert and Jan van Eyck. The altarpiece is considered a masterpiece of European art and one of the world's treasures, it was “the first major oil painting,” and it marked the transition from Middle Age to Renaissance art.[2]