Doriscus was an ancient settlement in Thrace (modern-day Greece), on the northern shores of Aegean Sea. It was notable for remaining in Persian hands for many years after the Second Persian invasion of Greece, and remained thus known as the last Persian stronghold in Europe. The ancient city was located in a vast plain of the same name, where the River Hebrus was crossing in the middle. Herodotus (7.59) reports that Xerxes the Great, during his campaign of invading the Greek City States in 480 BCE, was the first place he stopped to review his troops after crossing the Hellespont.