his activity in the court is comparatively well documented. He served as court artist and diplomat, and was a senior member of the Tournai painters' guild. On 18 October 1427, the Feast of St. Luke, he travelled to Tournai to attend a banquet in his honour, also attended by Robert Campin and Rogier van der Weyden. A court salary freed him from commissioned work, and allowed a large degree of artistic freedom. Over the following decade van Eyck's reputation and technical ability grew, mostly from his innovative approaches towards the handling and manipulating of oil paint. Unlike most of his peers, his reputation never diminished and he remained well regarded over the following centuries. His revolutionary approach to oil was such that a myth, perpetuated by Giorgio Vasari, arose that he had invented oil painting. His brother Hubert van Eyck collaborated on Jan's most famous works, the Ghent Altarpiece, generally art historians believe it was begun c. 1420 by Hubert and completed by Jan in 1432. Another brother, Lambert, is mentioned in Burgundian court documents, and may have overseen his brother's workshop after Jan's death. Maturity and success Considered revolutionary within his lifetime, van Eyck's designs and methods were heavily copied and reproduced. His motto, one of the first and still most distinctive signatures in art history, ALS ICH KAN ("AS I CAN"), a pun on his name, first appeared in 1433 on Portrait of a Man in a Turban, which can be seen as indicative of his emerging self-confidence at the time. The years between 1434 and 1436 are generally considered his high point when he produced works including the Madonna of Chancellor Rolin, Lucca Madonna and Virgin and Child with Canon van der Paele. Around 1432, he married Margaret who was 15 years younger. At about the same time he bought a house in Bruges; Margaret is unmentioned before he relocated, when the first of their two children was born in 1434. Very little is known of Margaret; even her maiden name is lost – contemporary records refer to her mainly as Damoiselle Marguerite. She may have been of aristocratic birth, though from the lower nobility, evidenced from her clothes in the portrait which are fashionable but not of the sumptuousness worn by the bride in the Arnolfini Portrait. Later, as the widow of a renowned painter Margaret was afforded a modest pension by the city of Bruges