To go briefly through the various stages. The heaven of the Moon is that in which appear the spirits of those who having taken vows have under compulsion or persuasion abandoned them; Mercury contains statesmen and men of affairs; Venus those who have been over-much swayed by indulgence in earthly love. It must be observed that, according to the astronomy of the time, the shadow of the Earth, cast into space by the Sun, extended as far as the orbit of Venus. The spirits in these three spheres therefore form a group by themselves: being distinguished by the fact that they had allowed earthly cares and pleasures to obtain too strong hold of them, to the injury of their spiritual development. In these three spheres respectively the representative speakers are Piccarda Donati, sister of Dante’s friend Forese, and of Corso, the leader of the “Black Guelfs;” the Emperor Justinian; and Carlo Martello, the titular king of Hungary, son of Charles II., king of Naples, who is followed by Cunizza, sister of the Ghibeline chief, Ezzelino da Romano, and Folco of Marseilles, who began as a troubadour and became bishop of his native city. Although in one sense the inhabitants of the three lower spheres may be said to have attained a less perfect blessedness than those to whom the rest of heaven is assigned, it must not be supposed that they are conscious of any lack. All have their places in the highest or Empyrean heaven, and all sense of sorrow for past imperfections is at an end. We must indeed suppose that, as with Dante himself, the imperfections have been effaced by the discipline of Purgatory, and their remembrance washed away by the water of Lethe. With the sphere of the Sun, however, we arrive for the first time in the presence of those who have lived so as to earn the full honour of sanctity, and find ourselves amongst canonised saints. Even here Dante has shown himself, as usual, independent of conventional or official restrictions. In his introduction of St. Thomas Aquinas and St. Bonaventura he merely anticipates the formal decision of the Church; but in “Peter of Spain,” that is Pope John XXI. (the only historical Pope whom he places in Paradise), he selects for special honour a man who was by no means free from grave suspicion of heresy, and who has never been canonised. As Dante never did anything without a reason we must suppose that some now forgotten merit earned for the Spanish logician a place beside Nathan, Chrysostom, and Anselm. It is by these and such men as these, great teachers and thinkers, that the heaven of the Sun is occupied; the reason no doubt being that as the Sun is the source of light and the promoter of growth in the physical world, so are these in the spiritual.