Perinthus (Turkish Eski Eregli, old Heraclea) was an ancient town of Thrace, on the Propontis, 22 miles west of Selymbria , strongly situated on a small peninsula on the bay of that name.

It is said to have been a Samian colony, founded about 599 BC. According to John Tzetzes, its original name was Mygdonia; later it was called Heraclea (Heraclea Thraciae, Heraclea Perinthus). It is famous chiefly for its stubborn and successful resistance to Philip II of Macedon in 340 BCE; at that time it seems to have been more important than Byzantium itself.

This entry was originally from the 1911 Encyclopedia Britannica.