Commentary Par XVIII 124

The second of the three concluding apostrophes is addressed to the souls of the just rulers, whom he contemplates, as he writes these words, in the Empyrean.  Nowhere in this passage does the poet rise to a higher pitch of blissful contemplation than here, where he even now 'holds in mind' those whom he has previously seen in this heaven.  See C.Par.XVIII.118-136.