Alcetas (in Greek Ἀλκέτας; died 320 BC), the brother of Perdiccas and son of Orontes from Orestis, is first mentioned as one of Alexander the Great's generals in his Indian expedition. On the death of Alexander, he espoused his brother's party, and, at his orders, murdered in 322 BC Cynane, the half-sister of Alexander the Great, when she wished to marry her daughter Eurydice to Philip Arrhidaeus, the nominal king of Macedon. At the time of Perdiccas' murder in Egypt in 321 BC, Alcetas was with Eumenes in Asia Minor engaged against Craterus; and the army of Perdiccas, which had revolted from him and joined Ptolemy, condemned Alcetas and all the partizans of his brother to death. The war against Alcetas, who had now left Eumenes and united his forces with those of Attalus, was entrusted to