Their answer came in the form of the Western Turkic Khaganate incursion into Central Asia .
Even with the growth of Persian military power under Khosrow 's reforms , the Sasanians were still uneasy at the prospect of attacking the Hephthalites on their own and sought allies .
Sasanians ' answer came in the form of the Western Turkic Khaganate incursion into Central Asia .
Even with the growth of Persian military power under Khosrow 's reforms , the Sasanians were still uneasy at the prospect of attacking the Hephthalites on their own and sought allies .