Pentarchy (from the Greek Πενταρχία, Pentarchía, from πέντε pénte, "five", and ἄρχειν archein, "to rule") is a model of Church organization historically championed in the Eastern Orthodox Church. It was formulated in the laws of Emperor Justinian I (527–565) of the Roman Empire. In the model, the Christian church is governed by the heads (patriarchs) of the five major episcopal sees of the Roman Empire: Rome, Constantinople, Alexandria, Antioch, and Jerusalem.[3]