Thucydides writes extensively about Cranii in his History of the Peloponnesian War.
In 431 BCE, it joined the Athenian alliance, together with the other Cephallenian towns;[1] in consequence of which the Corinthians made a descent upon the territory of Cranii, but were repulsed with loss.
[2] In 421 BCE the Athenians settled at Cranii helot deserters of Sparta and the Messenians who were withdrawn from Pylos on the surrender of that fortress to the Lacedaemonians.
[7][8][9] William Martin Leake, who visited in the 19th century, remarks that "the walls of Cranii are among the best extant specimens of the military architecture of the Greeks, and a curious example of their attention to strength of position in preference to other conveniences; for nothing can be more rugged or forbidding than the greater part of the site.
The enclosure, which was of a quadrilateral form, and little, if at all, less than three miles (5 km) in circumference, followed the crests of several rocky summits, surrounding an elevated hollow which falls to the south-western extremity of the gulf of Argostóli."