Artaxerxes V, also known as Bessus (died summer 329 BC) was a prominent Persian (Iranian) satrap of Bactria in Persia, and later self-proclaimed king of the Persian Empire. According to classical sources, he killed his predecessor and relative, Darius III, after the Persian army had been defeated by Alexander the Great.
In the Battle of Gaugamela (October 1 331 BC), in which Alexander defeated Darius III, Bessus commanded the left wing of the Persian army, chiefly composed by troops of his satrapy, who had only been merely mobilized before the battle of Issus. The envelopment ordered by Darius failed and the Persians lost the battle after hours of fierce fighting. He survived the loss and remained with his king, whose routed army eluded Alexander's forces and spent the winter in Ecbatana. The next year Darius III attempted to flee to Bactria in the east. Bessus, conspiring with fellow satraps, deposed Darius III. He likely intended to surrender the king to the Macedonians, but Alexander ordered his forces to brutally pursue the Persians even after receiving word of Darius' arrest.
According to sources, the panicked conspirators mortally wounded Darius III and left him to be found by a Macedonian soldier. The Babylonian Chronicle known as BCHP 1 indicates this happened in July 330. The site has been identified near modern Ahuan.
Bessus immediately proclaimed himself king and adopted the throne name Artaxerxes (V). His self-proclaimed ascension was logical, since the satrap of Bactria, known as mathišta, was the noble next in the line of succession to the Persian throne. But since most of the Persian empire had been conquered and Bessus only ruled over a loose alliance of renegade provinces, historians do not generally regard him as an official Persian king.
Bessus returned to Bactria and tried to organize a resistance among the eastern satrapies. Alexander was forced to move his force to suppress the uprising in 329 BC. Frightened by the approaching Macedonians, Bessus's own people arrested and surrendered him.
Alexander ordered that Bessus's nose and ears be cut off, which was a Persian custom for those involved in rebellion and regicide; the Behistun inscription relates that Darius the Great punished the usurper Phraortes in a similar manner.
Ancient reports contradict each other about the cause of his death. Quintus Curtius Rufus, the historian, says he was crucified in the place where Darius III had been killed, Arrian states that he was tortured and then decapitated in Ecbatana, and Plutarch suggests that he was torn apart in Bactria after a Macedonian trial.