In 490 BCE, Datis and Artaphernes (son of the satrap Artaphernes) were given command of an amphibious invasion force, and set sail from Cilicia. The Persian force sailed first to the island of Rhodes, where a Lindian Temple Chronicle records that Datis besieged the city of Lindos, but was unsuccessful. The fleet sailed next to Naxos, to punish the Naxians for their resistance to the failed expedition the Persians had mounted there a decade earlier. Many of the inhabitants fled to the mountains; those that the Persians caught were enslaved. The Persians then burnt the city and temples of the Naxians. The fleet then proceeded to island-hop across the rest of the Aegean on its way to Eretria, taking hostages and troops from each island.

The task force sailed on to Euboea, and to the first major target, Eretria. The Eretrians made no attempt to stop the Persians from landing or advancing and thus allowed themselves to be besieged. For six days, the Persians attacked the walls, with losses on both sides; however, on the seventh day two reputable Eretrians opened the gates and betrayed the city to the Persians. The city was razed, and temples and shrines were looted and burned. Furthermore, according to Darius's commands, the Persians enslaved all the remaining townspeople.