Divine Comedy, Longfellow's Translation, Purgatory

"To run o''er better waters hoists its sail The little vessel of my genius now, That leaves behind itself a sea so cruel; And of that second kingdom will I sing Wherein the human spirit doth purge itself, And to ascend to heaven becometh worthy. But let dead Poesy here rise again, O holy Muses, since that I am yours, And here Calliope somewhat ascend, "