Circle of Magic

Circle of Magic is a quartet of fantasy novels by Tamora Pierce, set in Emelan, a fictional realm in a pseudo-medieval and renaissance era. It revolves around four young mages, each specializing in a different kind of magic, as they learn to control their extraordinary and strong powers and put them to use. It is followed by another quartet, The Circle Opens, which takes place four years later, and the standalone book The Will of the Empress, which takes place several years after that.