Complex sentence: The date is 13 October 79AD which would have been likely during the author's lifetime and coincides with the date given by Pliny the Younger for the eruption of Vesuvius, "IX kal Sept" in his description.
Split into simpler sentences: The date is 13 October 79AD which would have likely been during the author's lifetime. It coincides with the date given by Pliny the Younger for the eruption of Vesuvius, "IX kal Sept" in his description.