Delian League
It can be seen, however, that the First Peloponnesian War may have hastened the transition of the Delian League from an Athenian-dominated alliance to an Athenian-ruled empire. During the early years of the war, Athens and her non-Delian allies scored a series of victories. However, the collapse of the simultaneous Delian League expedition in Egypt in 454 BC caused panic in Athens, and resulted in decreased military activity until 451 BC, when a five-year truce was concluded with Sparta. During the panic, the treasury of the League was moved from Delos to the perceived safety of Athens in 454 BC. Although Athens had in practice had a hegemonic position over the rest of the league since the rebellion of Naxos (470/467 BC) was put down, the process by which the Delian league gradually transformed into the Athenian Empire accelerated after 461 BC. The transfer of the treasury to Athens is sometimes used as an arbitrary demarcation between the Delian League and the Athenian Empire. An alternative 'end-point' for the Delian League is the final end of hostilities with the Persians in 450 BC, after which, despite the fact that the stated aims of the League were fulfilled, the Athenians refused to allow member states to leave the alliance.