Multiple stellar populations in star clusters is a widespread phenomenon. They are observed to come in (at least) two flavours: either as multiple star formation episodes observed in young star clusters, or as multiple chemical abundance patterns observed in most old globular clusters, as well as in some intermediate-age star clusters. I will present a novel approach explaining why some clusters experience multiple star formation episodes, and how this approach allows the chemical evolution of a star cluster to be decoupled from the shape of its star formation history. This decoupling has the tremendous advantage of explaining the great diversity observed in star cluster properties, from ‘jagged’ star formation histories to smooth ones and from chemically-homogeneous clusters to inhomogeneous ones.