The Ghent Altarpiece, also called the Adoration of the Mystic Lamb, is a very 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 a prominent example of the transition from Middle Age to Renaissance art and is considered a masterpiece of European art, identified by some as "the first major oil painting."