While Mutahharten ultimately repelled Ali, the latter was replaced by his vizier Kadi Burhan al-Din (r. 1381–98), who was determined to restore the sultanate's former boundaries.

Often overpowered by his enemies, Mutahharten forged alliances with various groups but did not hesitate to turn against his former allies, such as the Aq Qoyunlu, when he saw fit.

On the other hand, Mutahharten's relations with the Empire of Trebizond and his Christian subjects were consistent, as he favored them for their economic contribution to his realm through trade.

After Kadi Burhan al-Din's death, Mutahharten faced a new threat from the Ottoman state, when Bayezid I demanded he surrender Erzincan.

Erzincan and the region around was located south of the Empire of Trebizond, a Christian state in coastal northeastern Anatolia (modern-day Turkey).

Although not part of it, Erzincan had significant commercial links to Trebizond, being mostly inhabited by Christian Armenians but administered by a Muslim ruler.

His core territory stretched from the Erzincan Plain southwards to the Upper Euphrates Valley near Çaltı.

[8] Pir Husayn (r. 1362–79), who was originally the ruler of Karahisar, arrived in Erzincan on 8 June 1362 and succeeded Ahi Ayna Beg.

In Ta'rīkh-i taqwīm authored by the 14th-century historian Abu Bakr Qutbi, Pir Husayn is mentioned as an emīr-zāda (lit.

He "gained independence" on 10 July,[9] having clashed with emirs opposing his rule, who eventually fled to Bayburt and Tercan.

[9] Although there is a coin specimen minted in Erzincan for the Eretnid sultan Ala al-Din Ali (r. 1366–80) dating back to 1366 signifying Erzincan's continued allegiance, Pir Husayn most likely exercised further autonomy, especially following the temporary political vacuum caused by the demise of Ali's predecessor, Ghiyath al-Din Muhammad I (r. 1352–54, 1355–1365), in 1365.

[11] While early Ottoman sources mention that Mutahharten was of Tatar origin,[12] in Bazm u Razm, Astarabadi referred to him as the nephew of Eretna,[9] who was of Uyghur descent.

[16] Mutahharten sent an embassy to Sivas, where the Eretnid military headquarters were located, to signal he would be willing to bestow control of Erzincan, fearing the economic impact of the war.

[18] Kadi Burhan al-Din's (r. 1381–98) rise to power as the regent of Ali's successor Muhammad II Chelebi (r. 1380–81), and his aim at re-imposing authority over the region, prompted Mutahharten to form alliances with Burhan al-Din's rivals and other claimants to the Eretnid throne, such as Shadgeldi, Emir of Amasya (r. 1359–60/1, 1361/2–81).

[19] Mutahharten sent an embassy to Burhan al-Din and demanded that he return the throne to Ali's son, Muhammad II Chelebi, who was too young to rule.

Although Kadi Burhan al-Din released his embassy, he sent Shadgeldi's head to Erzincan in 1381 as a warning after having defeated him on the battlefield.

When his authority in the region became apparent and an internal conflict among the rebels began, he focused on his struggle east against Mutahharten.

[25] In late 1386, Timur (r. 1370–1405), a Turco-Mongol warlord who attempted to invoke the legacy of Genghis Khan, invaded west Iran and was planning his invasion of the Armenian highlands from his military camp in Karabakh.

He stationed his army on the right bank of Murat River near the town of Gulushkerd, confronting the Aq Qoyunlu forces on the opposite side.

The chronicles of the Trapezuntine historian Michael Panaretos of 1380–90s lack any mention of clashes with Turks, other than the campaign of Emperor Alexios III (r. 1349–90) on the Chepni, most probably because there were no direct border conflicts, and the trade through Trebizond continued.

In response to Timur's inquiry about these complaints, Mutahharten openly agreed that he especially favored the Christians for the benefit of trade.

Instead, Mutahharten relied on Timur, who was unable to diplomatically resolve the dispute over Erzincan but conquered Sivas in August 1400.

[36] Mutahharten was ultimately released and restored as the ruler when Qara Yusuf, who had been given control of the place, did not fare well with the locals.