Complex sentence: They were based on the Greek Dionysia and the Dionysian mysteries, and probably arrived in Rome c.200 BC via the Greek colonies in southern Italy, and from Etruria, Rome's northern neighbour.
Split into simpler sentences: They were based on the Greek Dionysia and the Dionysian mysteries. They arrived in Rome c.200 BC via the Greek colonies in southern Italy, and from Etruria, Rome's northern neighbour.