How did the revolt of Boeotia weaken Athenian power in the 440s BCE?

The revolt of Boeotia in 447 or 446 BCE significantly weakened Athenian power by triggering a cascade of military and strategic crises. After defeating a small Athenian army, the Boeotian revolt encouraged Euboea and Megara to also rebel against Athenian control.12

This series of uprisings created a severe military emergency, compounded by the appearance of a Spartan army in Attica. To resolve the crisis, Pericles negotiated the Thirty Years’ Peace, which forced Athens to relinquish its mainland possessions and abandon its control over Boeotia and the Megarid.12

The loss of Megara was particularly damaging, as it removed a critical buffer and allowed Spartan forces to threaten Attica more easily. Consequently, Athens was compelled to shift its focus toward maintaining a strictly maritime empire, a strategic pivot that led Pericles to construct a third Long Wall to ensure the city could be defended as an island.1