From David Bentley Hart’s Atheist Delusions, page 196:
. . .
This same drama, or one very like it, would be played out again and again throughout the history of Christendom, and often-though not always-the temporal power would emerge victorious over the spiritual. Still, a principle had been established on the day of Theodosius’s penance: the state could never again enjoy the unquestioned divine authority or legitimacy it had possessed before the rise of Christianity. If Theodosius’s imposition of Catholic orthodoxy on the empire was in some sense the Christian revolution’s greatest defeat (and it was), it was also an irremediable blow to the ultimacy of the state; and this much, at least, the church bequeathed to the future. In some sense the ferment, fecundity, and turmoil of later Western history-political, social, ideological, and so on-was born in this moment when the unhappy marriage of church and state also, quite unexpectedly, began to desacralize the state. Of course, from that point on it was inevitable that these two allied but essentially irreconcilable orders would continue to struggle for advantage, one over the other. And only in the early modern period would that struggle be decided, with the reduction of the church to a state cult, as part of the West’s transition to late modernity’s cult of the state.