Why did Athenians build a smaller defensive wall after the Heruli sack?

Following the sack of Athens by the Heruli in 267 ce, the city’s defensive strategy shifted significantly. The previous, larger circuit of walls had proven ineffective against the invaders, who successfully captured and burned the lower town, including the Agora area.1

In response, the Athenians abandoned the outer circuit and established a new, much smaller defensive line located north of the Acropolis. This construction, which occurred during the reign of the emperor Probus (276–282 ce), was built using materials salvaged from the ruined buildings of the lower town. By confining the city to this narrow circuit, the Athenians prioritized a more defensible position, effectively leaving the Agora and other outlying areas outside the new walls for several generations.1