Paros was a major place in the Aegean. It was colonized by settlers from Athens and eventually colonized itself Thasos and Parium. They also founded the colony of Pharos on Illyria in 385 BCE, which explains why the coinage of both cities contains a goat.
Around the time of the Persian Wars, Paros was dependent upon Naxos. They joined the Persian side and as a result were besieged by Athens after the war. However, in a sign of their power, that siege failed.
In the second Persian War, they again sided with the Persians, though their troops did not see action, and were summarily punished with a large fine by Themistokles. They were forced to join the Delian league and had among the highest dues. In 357 BCE, along with Chios, it left the confederacy.