Istemi Khagan of the Göktürk Khaganate | 552 – 575

Here is my current portrait of Istemi Khagan as a middle-aged ruler in Sogdia.

Although he was originally named Yabgu (viceroy), he administered the entire western territory of the Göktürk Khaganate completely independently from the Khagans in the east for more than two decades.

As the younger brother of Bumin, Istemi more than doubled the size of the Türk Empire within merely eight years. Some of his accomplishments are the complete expulsion of the Avar-Rouran from Asia, the destruction of the Hephthalites (Ak Hun) with assistance from the Sassanians, and laying the groundwork for the Turkic-Sogdian synthesis that would last four centuries.

Under Istemi's rule, the Göktürks massively expanded their geopolitical influence, gained control of the Silk Road(s), and even forged an alliance with the faraway Byzantine (Roman) Empire in Constantinople.

But most importantly, Istemi fulfilled Bumin Khagan's initial dream and united all – ALL! – Turkic peoples west of the Altai Mountains.

In my humble personal opinion, Istemi is the most important ruler of the entire Göktürk era (552–745) right after Bumin.