For Sedulius Scottus (On Christian Rulers), royal piety was both royal and pious. He urged rulers to practice Christian virtues in their political lives.
He encourages kings to a life of prayer, giving several examples of how the Lord “shielded [men] from the dangers of death by holy prayers and divine help rather than by physical arms” (81). Kings should show humility, particularly in their attitude toward priests, illustrating with the famous episode of Ambrose’s “profitable rebuke” to the emperor Theodosius (71-3). He quotes Constantine’s lengthy prayer of thanksgiving from Cassiodorus to show that rulers must “offer sacrifices of thanksgiving to Almighty God” for all military and political success (89; the prayer may be apocryphal, but it accurately reflects Constantine’s theopolitical convictions).
There’s little hint that Christian virtues are at odds with political power as such, though Christian virtuesare clearly at war with certain habits of political power. For various reasons, this perspective was lost in the early modern period, and we are left to reconstruct a political piety that is at once fully political and deeply pious.