Harpers Dictionary of Classical Antiquities (1898)

An Athenian general, son of Alcisthenes, who obtained considerable reputation during a part of the Peloponnesian War. When the Spartan monarch Agis made an inroad into Attica, Demosthenes, on his part, harassed the coasts of the Peloponnesus, and seized upon and fortified the Messenian Pylos. This led to the affair of Sphacteria (q.v.), in which he had a conspicuous, or, rather, the principal share. He was afterwards sent with an armament to the relief of Nicias before Syracuse; but, by his precipitate measures there, brought defeat upon himself and the consequent ruin of the whole expedition. Demosthenes and Nicias were both put to death while in prison, notwithstanding the endeavours of the Spartan commander Gylippus to save their lives. Another account, alluded to by Plutarch, makes them to have been stoned to death (Thuc.iv. 3 foll.; Plut. Nic.).