But they had come to the very crown of their glory.  When a war arose between the Corinthians and the Corcyrans, who inhabited the isle now called Corfu, the Corcyrans asked to be made allies of Athens, and a fleet was sent to help them; and as the Corinthians held with Sparta, this brought on a great war between Athens and Sparta, which was called the Peloponnesian war, and lasted thirty years.  It was really to decide which of the two great cities should be chief, and both were equally determined.