Before Parthia stepped onto the world stage, there was another empire that stood in its way, the Seleucids. The Seleucids were the direct successors of Alexander the Great. When Alexander died, his Empire was divided into many pieces, only to end up in four different sections due to throne squabbling that led to war. These four sections went on to become states of their own, all claiming to be the legitimate successor of Alexander. The four kingdoms/empires were the Ptolemaic Kingdom ruled by Ptolemy I, the Cassander kingdom ruled by Cassander, the Kingdom of Lysimachus ruled by Lysimachus, and finally, the Seleucid Empire ruled by Seleucus Nicator, who inherited Alexander’s eastern domains.
Seleucus inherited a rather large chunk of land, extending from Anatolia in the west to the borders of India in the east. You could say he hit the “lottery” but at the same time he inherited much more than he bargained for, more so for the future inheritors of this vast domain.
One of the biggest issues in controlling such a vast amount of land is holding on to it. One has to consider, especially those in the Seleucid administration, that there are going to be language barriers, but even more important than language barriers are the cultural barriers. To deal with these multiple concerns the administration found that it was easier to allow the locals to govern under Greco-Macedonian supervision. In this way, the Seleucid kings could control their eastern provinces more effectively. However, while the Seleucid kings allowed the locals of their eastern provinces to govern, it created friction between the two cultures. In other words, as you shall read, the Seleucid kings unintentionally ignored their satraps in the east. Reason for this was due to war with their western neighbors and internal political struggles. All of which diverter their attentions and caused their eastern satraps to slowly break from the empire.
Ignoring the various peoples on the Iranian Plateau and areas farther to the east under Seleucid control caused many of them, including Greco-Macedonians, to question the intent of their masters in the west. After doing so, many in the east would secede. This secession from the Seleucids enticed certain nomadic tribes, such as the Aparni (Parthians), to invade, conquer, confiscate, and colonize the weakest breakaway provinces. The Seleucid regime’s uncertainty allowed a small tribe from the north to invade a breakaway province considered Seleucid territory that, in turn, would go on to nearly re-conquer everything Alexander the Great had subdued almost a century earlier.