 Plymouth 's early history extends to the Bronze Age , when a first settlement emerged at Mount Batten . This settlement continued as a trading post for the Roman Empire , until it was surpassed by the more prosperous village of Sutton , now called Plymouth . In 1620 , the Pilgrim Fathers departed Plymouth for the New World and established Plymouth Colony – the second English settlement in what is now the United States of America . During the English Civil War the town was held by the Parliamentarians and was besieged between 1642 and 1646 . 
