The Belgian publisher La Procure à Namur organised a drawing contest.

They were interested in finding talented artists to illustrate works for school children.

Marlier's collaboration with La Procure à Namur lasted more than 25 years.

Pierre Servais at Casterman, a Belgian publishing company, began to notice Marlier's drawings in 1951.

From 1954, Marlier illustrated the children's series Martine, with the stories written by Gilbert Delahaye.