 Complete the following phrase:  Although he first became a member of the Cercle artistique de Luxembourg, he joined Joseph Kutter, Nico Klopp and others as a co-founder of the Luxembourg secession movement which succeeded in promoting modern art. After exhibiting his work both in Luxembourg and Brussels, he was charged by the State to paint his monumental work Terres Rouges Red Lands for the Luxembourg pavilion at the 1937 World Exhibition in Paris. In 1939, together with Jean Schaak, he exhibited large decorative panels at the 