While thus the most important successes were gained towards the north,
the king at the same time extended his dominions towards the east and
the west. The Lesser Armenia was annexed by him and converted from a
dependent principality into an integral part of the Pontic kingdom;
but still more important was the close connection which he formed with
the king of the Greater Armenia.
He not only gave his daughter
Cleopatra in marriage to Tigranes, but it was mainly through his
support that Tigranes shook off the yoke of the Arsacids and took
their place in Asia. An agreement seems to have been made between
the two to the effect that Tigranes should take in hand to occupy
Syria and the interior of Asia, and Mithradates Asia Minor and
the coasts of the Black Sea, under promise of mutual support;
and it was beyond doubt the more active and capable Mithradates
who brought about this agreement with a view to cover his rear
and to secure a powerful ally.