Justin I
In the years following Chalcedon the patriarchs of Constantinople intermittently remained in communion with the non-Chalcedonian Patriarchs of Alexandria and Antioch (see Henotikon), while Rome remained out of communion with the latter and in unstable communion with Constantinople. It was not until 518 that the new Byzantine Emperor, Justin I (who accepted Chalcedon), demanded that the church in the Roman Empire accept the council's decisions.