Complex sentence: Year 340 BC was a year of the pre-Julian Roman calendar.In the Roman Empire it was known as the Year of the Consulship of Torquatus and Mus (or, less frequently, year 414 "Ab urbe condita").
Split into simpler sentences: Year 340 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Torquatus and Mus (or, less frequently, year 414 "Ab urbe condita").