Note 163 — CANTO I.
James Romanes Sibbald translation
That planet: On the Ptolemaic system, which, as perfected by the Arabian astronomers, and with some Christian additions, was that followed by Dante, the sun is reckoned as one of the seven planets; all the others as well as the earth and the fixed stars deriving their light from it. Here the sunlight may signify the Divine help granted to all men in their efforts after virtue.