Iotapa was of Median, Armenian and Greek descent. She was the daughter and one of the children born to King Artavasdes I of Media Atropatene and his wife, Athenais a daughter of the Commagenean Monarchs Antiochus I Theos and Isias Philostorgos.
In 33 BC, she was engaged to her distant relative, the Ptolemaic Prince Alexander Helios, son of Greek Ptolemaic Queen Cleopatra VII of Egypt and Roman Triumvir Mark Antony. The background to this was as follows. In 35 BC Artavasdes I offered Antony an alliance against Parthia, and Antony gladly accepted. To deepen this friendship Alexander Helios, the son of Antony and Cleopatra VII, was betrothed to Artavasdes I’s daughter Iotapa, although both were young children in 34 BC.
In 33 BC Antony met his coalition partner on the river Araxes; they agreed that Antony should support Artavasdes I against Parthia and that the Median King should help Antony against Octavian. They interchanged parts of their troops. The domain of Artavasdes I was enlarged with parts of Armenia. Antony had returned a standard that the Median king had taken from Oppius Statianus in 36 BC, and also took Iotapa along with him. With the help of the Roman reinforcements Artavasdes I was initially able to repulse the Parthian attack. Before the Battle of Actium, Antony called back his Roman troops without sending back the Median reinforcements. This time Phraates IV defeated Artavasdes I who was captured in 30 BC.
In 30 BC Iotapa left Alexandria after Egypt was invaded by Octavian (future Roman Emperor Augustus) and his army. During Artavasdes' imprisonment, a civil war between the Parthians later took place, which gave him the opportunity to escape prison. He took refuge with Augustus, who received him with friendliness, gave him back his daughter Iotapa and made him a Client King of Lesser Armenia.
Iotapa thereby returned to her father and sometime after 30 BC, she married her maternal cousin King Mithridates III of Commagene. Through this marriage, she became a Queen of Commagene and bore Mithridates a daughter called Aka II of Commagene; a son future Prince, successor Antiochus III of Commagene and two daughters, both princesses called Iotapa.
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