Originally the ruler of Karahisar, he arrived in Erzincan on 8 June 1362 and claimed the throne that was occupied by Ahi Ayna, who died on 2–3 July.
Pir Husayn was originally the ruler of Karahisar and arrived in Erzincan on 8 June 1362 and succeeded Ahi Ayna, who died on 2–3 July 1362 reportedly as a shaheed (martyr).
In Abu Bakr Qutbi's Tarikh-i taqwim, Pir Husayn is mentioned as an emir-zada (lit.
[1] Pir Husayn's ascendance to the throne was not straightforward as Erzincan was in the midst of a civil war.
He "gained independence" on 10 July,[2] having clashed with emirs opposing to his rule, who eventually fled to Bayburt and Tercan.