After the death of Mithridates II of Parthia in 88 BCE, Tigranes took advantage of the fact that the Parthian Empire had been weakened by Scythian invasions and internal squabbling:

Scythian invasions (80 BC-20 AD)

The Orontids established their supremacy over Armenia around the time of the Scythian and Median invasion in the 6th century BC.

All these groups of north-western peoples apparently entered Indian mainland following the Scythian invasion of India.

A series of Scythian invasions, beginning in the 6th century BC, precipitated the demise of the Lusatian culture.

Beginning in the 6th century several waves of Scythian invasions went through the Polish lands.

During later times, the area also witnessed Celtic and Scythian invasions.

After another interval, the Indo-Parthians were themselves forced out of their possessions in Afghanistan, Punjab, and Upper India by the Scythian invasion, and their only possible refuge then was in the south.

Further major "Scythian" invasions took place in 265-266 and possibly the largest of all, 267-268, which was a seaborne invasion which penetrated the Aegean Sea.

Scythian invasions (80 BCE - 50 CE)