Complex sentence: Year 345 BC was a year of the pre-Julian Roman calendar.In the Roman Empire it was known as the Year of the Consulship of Dorsuo and Camerinus (or, less frequently, year 409 "Ab urbe condita").
Split into simpler sentences: Year 345 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Dorsuo and Camerinus (or, less frequently, year 409 "Ab urbe condita").