Question: Who is Antiochus Iii Of Commagene's maternal grandfather?

Knowledge 1: Antiochus III of Commagene
Antiochus III Epiphanes (flourished 1st century BC and 1st century AD) was the ruler of the Kingdom of Commagene from 12 BC to 17 AD.He was the son and successor of King Mithridates III of Commagene and Iotapa, and of mixed Armenian, Greek and Median descent--the last through his mother.His parents were first cousins.When Antiochus died in 17 AD, his death created major issues for the kingdom, which was in political turmoil at the time.The reasons for this situation are unclear, but it may have been the consequence of his children, Antiochus and Iotapa, being too young to succeed their father.This may have meant that there was no effective authority to prevent civil unrest and unite the citizens of Commagene.Very little is known on his life and his reign as King.After Antiochus' death, two factions appeared: one led by noblemen who wanted Commagene to be placed under the rule of the Roman Empire and the other led by citizens who wanted Commagene's independence to be retained under the rule of their own king.Both factions sent embassies to Rome, seeking the advice and assistance of Emperor Tiberius to decide the future of Commagene.Tiberius decided to make Commagene a part of the Roman province of Syria.That decision was welcomed by many of the citizens by Commagene, which remained under Roman rule until Caligula restored the kingdom to Antiochus’ children in 38 AD.Antiochus III and his son are honoured on the Philopappos Monument in Athens, Greece, dedicated to his great-grandson, Prince Gaius Julius Antiochus Epiphanes Philopappos, who was a prominent and respected citizen in Athens.In the left figure of the monument is a statue of Antiochus III's son, Antiochus IV.Below Antiochus IV is an inscription that states "King Antiochus son of King Antiochus". [SEP] Knowledge 2: Iotapa (daughter of Artavasdes I)
Iotapa (born in 43 BC-unknown date of death) was a princess of Media Atropatene, daughter of King Artavasdes I of Media Atropatene.She was Queen consort of King Mithridates III of Commagene.
Knowledge 1: Antiochus III of Commagene
Antiochus III Epiphanes (flourished 1st century BC and 1st century AD) was the ruler of the Kingdom of Commagene from 12 BC to 17 AD.He was the son and successor of King Mithridates III of Commagene and Iotapa, and of mixed Armenian, Greek and Median descent--the last through his mother.His parents were first cousins.When Antiochus died in 17 AD, his death created major issues for the kingdom, which was in political turmoil at the time.The reasons for this situation are unclear, but it may have been the consequence of his children, Antiochus and Iotapa, being too young to succeed their father.This may have meant that there was no effective authority to prevent civil unrest and unite the citizens of Commagene.Very little is known on his life and his reign as King.After Antiochus' death, two factions appeared: one led by noblemen who wanted Commagene to be placed under the rule of the Roman Empire and the other led by citizens who wanted Commagene's independence to be retained under the rule of their own king.Both factions sent embassies to Rome, seeking the advice and assistance of Emperor Tiberius to decide the future of Commagene.Tiberius decided to make Commagene a part of the Roman province of Syria.That decision was welcomed by many of the citizens by Commagene, which remained under Roman rule until Caligula restored the kingdom to Antiochus’ children in 38 AD.Antiochus III and his son are honoured on the Philopappos Monument in Athens, Greece, dedicated to his great-grandson, Prince Gaius Julius Antiochus Epiphanes Philopappos, who was a prominent and respected citizen in Athens.In the left figure of the monument is a statue of Antiochus III's son, Antiochus IV.Below Antiochus IV is an inscription that states "King Antiochus son of King Antiochus". [SEP] Knowledge 2: Aka II of Commagene
Aka II of Commagene also known as Aka II or Aka  was a Princess from the Kingdom of Commagene who lived in the second half of the 1st century BC & first half of the 1st century, who was of Armenian, Greek and Median descent.Aka II is one of the daughters born to the King of Commagene, Mithridates III who reigned from 20 BC until 12 BC from his cousin-wife Queen Iotapa, thus was a sister of Antiochus III of Commagene.She was mostly probably born, raised and educated in Samosata, the capital of the Kingdom of Commagene.Aka II is the namesake of Aka I of Commagene, a former Commagenian Princess who was the daughter of Antiochis of Commagene who was the first cousin of her parents.At an unknown date in the late first century BC, Aka II married an Egyptian Greek called Thrasyllus of Mendes and the circumstances that led Thrasyllus to marry Aka II are unknown.Aka II is known from a preserved incomplete poem, that mentions Aka II as the wife of Thrasyllus and mentions she was of royal origins.Thrasyllus was a Grammarian, Literary Commentator who served as the astrologer and became the personal friend of the Roman emperor Tiberius, who reigned from 14 until 37.As Tiberius had held Thrasyllus in the highest honor, Tiberius rewarded Thrasyllus for his friendship by giving him, Roman citizenship to him and his family.From given Roman citizenship, Aka II became known as "Claudia Aka", as her husband became known as "Tiberius Claudius Thrasyllus".Aka II died at an unknown date in the first century.Aka II bore Thrasyllus two known children:
Knowledge 1: Aka II of Commagene
Aka II of Commagene also known as Aka II or Aka  was a Princess from the Kingdom of Commagene who lived in the second half of the 1st century BC & first half of the 1st century, who was of Armenian, Greek and Median descent.Aka II is one of the daughters born to the King of Commagene, Mithridates III who reigned from 20 BC until 12 BC from his cousin-wife Queen Iotapa, thus was a sister of Antiochus III of Commagene.She was mostly probably born, raised and educated in Samosata, the capital of the Kingdom of Commagene.Aka II is the namesake of Aka I of Commagene, a former Commagenian Princess who was the daughter of Antiochis of Commagene who was the first cousin of her parents.At an unknown date in the late first century BC, Aka II married an Egyptian Greek called Thrasyllus of Mendes and the circumstances that led Thrasyllus to marry Aka II are unknown.Aka II is known from a preserved incomplete poem, that mentions Aka II as the wife of Thrasyllus and mentions she was of royal origins.Thrasyllus was a Grammarian, Literary Commentator who served as the astrologer and became the personal friend of the Roman emperor Tiberius, who reigned from 14 until 37.As Tiberius had held Thrasyllus in the highest honor, Tiberius rewarded Thrasyllus for his friendship by giving him, Roman citizenship to him and his family.From given Roman citizenship, Aka II became known as "Claudia Aka", as her husband became known as "Tiberius Claudius Thrasyllus".Aka II died at an unknown date in the first century.Aka II bore Thrasyllus two known children: [SEP] Knowledge 2: Aka I of Commagene
Aka I of Commagene also known as Aka I was a Princess from the Kingdom of Commagene, who lived in the 1st century BC.Aka I was of Greek and Armenian descent.Aka I was the daughter of Princess Antiochis of Commagene and the identity of her father is unknown.Her maternal grandparents were King Antiochus I Theos of Commagene and Queen Isias Philostorgos of Commagene.Very little is known on Aka I.She appeared to have died of unknown causes sometime between the late 30s or early 20s BC.AkaI was buried along with her maternal grandmother and her mother on a burial site called the Karakuş Tumulus.Her namesake was Aka II of Commagene.

Answer: Artavasdes I of Media Atropatene