Artabanus IV, also known as Ardavan IV (Parthian:𐭓𐭕𐭐𐭍), incorrectly known in older scholarship as Artabanus V, was the last ruler of the Parthian Empire from c. 213 to 224. He was the younger son of Vologases V, who died in 208. Name is the Latin form of the Greek Artábanos (), itself from the Old Persian *Arta-bānu ("the glory of Arta."). The Parthian and Middle Persian variant was Ardawān (). Reign Dynastic struggles and war with the Romans In , Vologases VI succeeded his father Vologases V as king of the Parthian Empire. His rule was unquestioned for a few years, till his brother Artabanus IV rebelled. The dynastic struggle between the two brothers most likely started about 213. Artabanus successfully conquered much of the empire, including Media and Susa. Vologases VI seems to have only managed to keep Seleucia, where he minted coins. The Roman emperor Caracalla sought to take advantage of the conflict between the two brothers. He tried to find a pretext to invade the Parthian Empire by requesting Vologases to send two refugees—a philosopher named Antiochus and a certain Tiridates, who was possibly either an Armenian prince or an uncle of Vologases. To the surprise of the Romans, Vologases had the two men sent to Caracalla in 215, thus denying him his pretext. Caracalla's choice of contacting Vologases instead of Artabanus shows that the Romans still saw him as the dominant king. Caracalla thus chose to preoccupy himself with an invasion of Armenia. He appointed a freedman named Theocritus as the leader of the invasion, which eventually ended in a disaster. Caracalla then once again sought to start a war with the Parthians. In another attempt to gain a pretext, he requested Artabanus to marry his daughter, which he declined. It is disputed whether Caracalla's proposal was sincere or not. Caracalla's choice to contact Artabanus shows that the latter was now considered the dominant king over Vologases, who would rule a small principality centered around Seleucia until 221/2. Artabanus soon clashed with Caracalla, whose forces he managed to contain at Nisibis in 217. Peace was made between the two empires the following year, with the Arsacids keeping most of Mesopotamia. However, Artabanus still had to deal with his brother Vologases, who continued to mint coins and challenge him. War with the Sasanians The Sasanian family had meanwhile quickly risen to prominence in their native Pars, and