Eusebius of Caesarea drew heavily on pagan philosophy in developing the first Christian political theology. His quotations from Plato’s most political work, the Laws, are so extensive that they are treated as a manuscript authority by modern editors. Yet Eusebius’s actual use of the Laws is oddly detached from Plato’s own political intentions in that work, adapting it to a model of philosophical kingship closer to the Republic and applied to the emperor Constantine. For Eusebius the Laws mainly shows the agreement of Christian and pagan morality, while his political theory centers on the establishment and maintenance of a Christian empire under a Christian emperor who is a philosopher-king. His view represents one of the fundamental political options in ancient Christianity, one that influenced later Byzantine political theology, but was largely rejected in the west.
Charles Norris Cochrane, Christianity and Classical Culture: A Study of Thought and Action from Augustus to Augustine (Oxford: Oxford University Press, 1942); Werner Jaeger, Early Christianity and Greek Paedeia (Cambridge, ma: Harvard University Press, 1962); Jaroslav Pelikan, Christianity and Classical Culture: The Metamorphosis of Natural Theology in the Christian Encounter with Hellenism (New Haven: Yale University Press, 1993).
See especially Norman H. Baynes, ‘Eusebius and the Christian Empire’, in Byzantine Studies and Other Essays(London: Athlone Press, 1955), pp. 168-72 (the essay was originally published in 1933), which relies heavily on Erwin Goodenough, ‘The Political Philosophy of Hellenistic Kingship’, Yale Classical Studies, 1 (1928), pp. 55-102. See also Francis Dvornik, Early Christian and Byzantine Political Philosophy: Origins and Background (Washington, dc: Dumbarton Oaks Center for Byzantine Studies, 1966), vol. 2, pp. 616-22; Eusebius: Life of Constantine, introduction, translation, and commentary by Avril Cameron and Stuart G. Hall (Oxford: Clarendon Press, 1999), p. 35.
Barnes, Constantine and Eusebius, pp. 265-66,argues that Eusebius likely met with Constantine only four times. Also, there is a revisionist current underway with respect to Eisebius’s generally supposed Arianism: see Christopher A. Beeley, The Unity of Christ: Continuity and Conflict in Patristic Tradition (New Haven: Yale University Press, 2012), ch. 2.
On the former see Cameron and Hall, Eusebius: Life of Constantine, pp. 3, 9-12; on the latter Drake, In Praise of Constantine, pp. 30-42. The latter is actually two speeches, a speech in honor of Constantine’s Tricennalia delivered on 25 July 336 (chs 1-10) and a speech delivered at the dedication of the Church of the Holy Sepulcher (chs 11-18) in late 335.
See, for example, Cicero, On Laws2.6.14, where the Laws is interpreted as a law code for the city described in the Republic. Among the Middle Platonists it was common to distinguish three different Platonic regimes, the best without hypotheses) in the Republic, the regime ‘with hypotheses’ in the Laws, and the ‘corrected’ regime of the Seventh Letter. See Alkinoos Didiaskalikos 188.8-9, 36-39 (anonymous), Prolegomena to Platonic Philosophy 26.37-45; and Apuleius On Plato 24-25. See also V.B. Lewis, ‘Politeia kai Nomoi: On the Coherence of Plato’s Political Philosophy’, Polity, 31 (1998), pp. 331-49.