Spithridates was a satrap

Satrap

Satrap was the name given to the governors of the provinces of the ancient Median and Achaemenid Empires and in several of their successors, such as the Sassanid Empire and the Hellenistic empires....

 of Lydia

Lydia

Lydia was an Iron Age kingdom of western Asia Minor located generally east of ancient Ionia in the modern Turkish provinces of Manisa and inland İzmir. Its population spoke an Anatolian language known as Lydian....

 and Ionia

Ionia

Ionia is an ancient region of central coastal Anatolia in present-day Turkey, the region nearest İzmir, which was historically Smyrna. It consisted of the northernmost territories of the Ionian League of Greek settlements...

 under the high king

High king

A high king is a king who holds a position of seniority over a group of other kings, without the title of Emperor; compare King of Kings.Rulers who have been termed "high king" include:...

 Darius III Codomannus

Darius III of Persia

Darius III , also known by his given name of Codomannus, was the last king of the Achaemenid Empire of Persia from 336 BC to 330 BC....

 and was one of the Persian commanders at the Battle of the Granicus

Battle of the Granicus

The Battle of the Granicus River in May 334 BC was the first of three major battles fought between Alexander the Great and the Persian Empire...

, in 334 BC

334 BC

Year 334 BC was a year of the pre-Julian Roman calendar. At the time, it was known as the Year of the Consulship of Caudinus and Calvinus...

, in which engagement, while he was aiming a blow from behind at Alexander the Great, his arm was cut off by Cleitus, son of Dropides. Diodorus

Diodorus Siculus

Diodorus Siculus was a Greek historian who flourished between 60 and 30 BC. According to Diodorus' own work, he was born at Agyrium in Sicily . With one exception, antiquity affords no further information about Diodorus' life and doings beyond what is to be found in his own work, Bibliotheca...

 calls him Spithrobates, and appears to confound him with Mithridates

Mithridates of Persia

Mithridates was a Persian of high rank, and son-in-law of the king Darius III, who was slain by Alexander the Great with his own hand, at the Battle of the Granicus in 334 BC, when he plunged his lance through Mithridates' face.-References:*Smith, William ; Dictionary of Greek and Roman Biography...

, the son-in-law of Darius, whom Alexander slew in the battle with his own hand; while what Arrian

Arrian

Lucius Flavius Arrianus 'Xenophon , known in English as Arrian , and Arrian of Nicomedia, was a Roman historian, public servant, a military commander and a philosopher of the 2nd-century Roman period...

records of Spithridates is related by Diodorus of his brother Rhoesaces.