Antiochus I Theos Dikaios Epiphanes Philorhomaios Philhellen (Ἀντίοχος ὁ Θεὸς Δίκαιος Ἐπιφανὴς Φιλορωμαῖος Φιλέλλην, meaning "Antiochos, the just, eminent god, friend of Romans and friend of Greeks", 86 – 31 , ruled 70 – 31 ) was king of the Greco-Iranian kingdom of Commagene and the most famous king of that kingdom.
The ruins of the tomb-sanctuary of Antiochus atop Mount Nemrut in Turkey were added to the UNESCO World Heritage list in 1987. Several sandstone bas reliefs discovered at the site contain some of the oldest known images of two figures shaking hands.
The reliefs portrayed Greco-Iranian deities, along with the goddess Commagene and also even Antiochus himself represented in a deified status. Antiochus was one of the last rulers of a Persian-Macedonian court before the advent of the Romans.
Antiochus I was the son of king Mithridates I Callinicus and queen Laodice VII Thea of Commagene. Antiochus was half Iranian, a distant member of the Orontid Dynasty and half Greek. Antiochus' father Mithridates was the son of King Sames II Theosebes Dikaios of Commagene and an unidentified woman. Mithridates was possibly related to the kings of Parthia and, in the light of archaeological discoveries at Mount Nemrut, claimed descent from Orontes and also claimed Darius I of Persia as an ancestor, thanks to Orontes' marriage to Rhodogune, daughter of Artaxerxes II, who was a descendant of king Darius I.
More certain are his dynastic connections to the Diadochi. Antiochus’ mother, Laodice VII Thea, was a Greek princess of the Seleucid Empire. Laodice's father was the Seleucid King Antiochus VIII Grypus, while her mother was a Ptolemaic princess and later Seleucid Queen Tryphaena (see Cleopatra VI of Egypt). Thus, Antiochus was a direct descendant of Seleucus I Nicator of the Seleucid Empire, Ptolemy I Soter of Egypt, Antigonus I Monophthalmus of Macedonia and Asia, Lysimachus of Thrace and the Macedonian regent, Antipater. These five men, the Diadochi 'successors', had served as generals under Alexander the Great.