Depends on what day the Hebrew calendar fell on that day and the Julian calendar holds all the notes on the Roman timeline regarding the birth. If he died on Nissan 15 (Mar/Apr or 1.15 & 7.15 I would think he was born on Tishri 15 (Sept/Oct or 1.15 & 7.15) as these are two New Years and calendars on Hebrew. That day could've fallen on what we now call 9.11. Most all of the "Men of Renown" written in Scriptures died the day they were born. This would be a way that was done. Spring or Nissan is when the world was created in thought, The Mind, but born of the "Body" or into life here in the fleshly world in Tishri.

Elul 23 was Creation; Elul 25 creation of Man. Elul is a 6th & 12th month.