In this paper we present an overview of various features of the structure of L10 magnetic phase. We discuss the various microstructural features which occur in these materials due to the changes in symmetry (translational and orientational domains) as well as the relationship between the crystal symmetry and features such as the thermodynamic order of the disorder to order phase transition. We also show the various ways that the magnetic moments of the elements align themselves in these alloys producing ferromagnetic and antiferromagnetic materials. Finally we discuss the way that the atomic order, composition and magnetic order affect the Curie temperatures of the FePd L10 alloys.