After the death of Alexander the Great in the year 324 B.C., his commanders divided his empire among themselves. Antigones took Macedonia and Ptolemius chose to take Egypt. The third commander, Seleukos, took Persia, Mesopotamia, Syria and Asia Minor. Since Armenia was an administrative part of Persia, it stood to reason that Armenia should also be included in the kingdom of Seleukos. But Armenia had already become independent, as we already have mentioned.
The successors of Seleukos tried in vain, during the 3rd century B.C., to conquer Armenia, but the country managed to defend itself successfully. After some territorial losses, the Seleucid kingdom was reduced to present-day Syria. At that time, around 222 B.C., the power-hungry Antiochos III came to power. He began a policy of expansion and managed finally to conquer Armenia. He divided Armenia into two parts: Armenia Major (greater Armenia), east of the Euphrates River, and Armenia Minor (lesser Armenia), west of the Euphrates and appointed a satrap for each part. The satraps he had chosen among the Armenian princes were Artashes (Artaxias) in Armenia Major and Zareh (Zariadrés) in Armenia Minor. The latter was a descendent of King Yervand, the first Armenian king.
But Antiochos III was not content with Armenia and turned his eyes towards Judea (Palestine) which he eventually conquered.. After a failed attempt at attacking Egypt, he expanded his borders to include all of Asia Minor.
Rome, which had just won its battle over Carthage, looked on the growing power of Antiochos III with concern. When Antiochos III conquered Asia Minor, the Romans could no longer just sit around and watch the “entrance” to their empire fall into the hands of a rival.. They attacked Antiochos III who suffered a heavy defeat. The losses were so great that the whole of his fast-growing empire was shattered and he was forced to content himself with the region that he had held in the beginning, i.e. Syria.
Fall of Seleucid empire
After the destruction of the Seleucid Empire, a Hellenistic Greek successor state of Alexander the Great's short-lived empire, a Hellenistic Armenian state was founded in 190 BC by Artaxias I. At its zenith, from 95 to 66 BC, Armenia extended its rule over parts of the Caucasus and the area that is now eastern Turkey, Syria and Lebanon. For a time, Armenia was one of the most powerful states in the Roman East. It came under the Roman sphere of influence in 66 BC.