Complex sentence: Year 342 BC was a year of the pre-Julian Roman calendar.In the Roman Empire it was known as the Year of the Consulship of Ahala and Rutilus (or, less frequently, year 412 "Ab urbe condita").
Split into simpler sentences: Year 342 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Ahala and Rutilus (or, less frequently, year 412 "Ab urbe condita").