Complex sentence: The panegyrist of 291 remarked that the meeting between Diocletian and Maximian over the winter of 290/91 was like the meeting of two deities; had the emperors ascended the Alps together, their bright glow would have illuminated all of Italy.
Split into simpler sentences: The panegyrist of 291 remarked that the meeting between Diocletian and Maximian over the winter of 290/91 was like the meeting of two deities. Had the emperors ascended the Alps together, their combined light would have shined over all of Italy.