Commentary Par XX 55-60

Since the spatial arrangement of the inhabitants of the Eagle's semicircular eyebrow is not chronological, the fact that Constantine (274-337) is the middle figure in it, and thus the highest, takes us by surprise, given the number and vehemence of Dante's outbursts against the Donation (e.g., [Inf XIX 115-117], [Purg XXXII 124-129]; and see Monarchia, which fairly seethes with them).  In this passage Dante settles for Constantine's good intent in his governance of the Eastern empire.  However, now this emperor knows that if the evil he unwittingly committed has not harmed him, it has nonetheless destroyed the world.  Dante may allow him salvation, but makes him pay for it eternally and dearly with this permanent wound in his self-awareness.  This does not efface the glory his good intention won him, but it does mar its beauty.