(born before 1395, Maaseik, Bishopric of Liège, Holy Roman Empire—died , before July 9, 1441, Bruges) Flemish painter. He is recorded in 1422 as a master painter working for John of Bavaria, count of Holland, and later was employed by Philip III the Good, duke of Burgundy. Securely attributed paintings survive only from the last decade of his career; 10 are signed and dated, an unusually large number for the period. He produced portraits and religious subjects that are unmatched for their technical brilliance, their intellectual complexity, and the richness of their symbolism; he perfected the newly developed technique of oil painting. His masterpiece is the Adoration of the Lamb (1432), known as the Ghent Altarpiece, which he painted with his brother Hubert ( 1370–1426). He is commonly regarded as the greatest northern European artist of the 15th century. His works were widely copied and avidly collected.