Commentary Purg IX 7-9

Much has been made of the phrase 'where we were' by the 'solar aurorans' in the hopes of counterposing the northern hemisphere (site of the solar Aurora at this hour in Italy) and the southern (where Dante and his companions are becoming sleepy).  However, Dante is probably not contrasting the two hemispheres but the glow in the night sky of purgatory that spreads above them and the darkness of their surroundings as night advances.  For a similar situation, consider [Purg II 8], the phrase 'là dov' i' era' (there where I was) by which Dante refers to his situation in the southern hemisphere looking at the stars from there.

      His figure of speech involves mixing metaphors, as the night is given feet, by which she measures her hours, and wings that do the same thing.  The meaning is that the time is between 8:30 and 9:00 pm.

      In a gesture of some charm but little possible historical foundation Benvenuto (DDP Benvenuto.Purg.IX.7-12) reads the passage as revelatory of Dante's studious burning, not only of the midnight oil, but even that of the pre-dawn hours: 'vir studiosus erat solitus vigilare per tres horas noctis et evigilare in aurora sicut nunc fecit.'