The Wars of the Delian League (477–449 BC) were a series of campaigns fought between the Delian League of Athens and her allies (and later subjects), and the Achaemenid Empire of Persia. These conflicts represent a continuation of the Greco-Persian Wars, after the Ionian Revolt and the first and second Persian invasions of Greece. The Greek alliance, centered around Sparta and Athens, that had defeated the second Persian invasion had initially followed up this success by capturing the Persian garrisons of Sestos and Byzantium, both in Thrace, in 479 and 478 BC respectively. After the capture of Byzantium, the Spartans elected not to continue the war effort, and a new alliance, commonly known as the Delian League, was formed, with Athens very much the dominant power. Over the next 30 years, Athens would gradually assume a more hegemonic position over the league, which gradually evolved into the Athenian Empire.