In around 513 BC, an army of the mighty Persian dynasty of the Achaemenids crossed the Bosphorus, after already having subdued the Thracians of Bithynia thirty years earlier. King Darius I's goal was a punitive expedition against the Scythians at the northern shores of the Black Sea. Most eastern Thracian tribes submitted peacefully, except of the Getai, who were defeated. More expeditions under the generals Megabazus and Mardonius as well as king Xerxes I followed, even though they only managed to secure the Aeagean coast.