Serving under the Il-Khans, they gained prominence when Sharaf al-Din Muzaffar was made governor of Maibud.

[citation needed] In the wake of the loss of Il-Khan authority in central Iran following the death of Abu Sa'id Bahadur Khan, Mubariz al-Din continued to carry out his expansionary policy.

He managed to escape from Shiraz and fled to Isfahan, but Mubariz al-Din pursued him, took the city and executed the Injuid ruler.

With the destruction of Injuid authority, the Muzaffarids were the strongest power in central Iran, and Shiraz was made their capital.

Mubariz al-Din's strength was such that when the khan of the Golden Horde, Jani Beg, sent an offer to make him a vassal, he was able to decline.

He defeated the khan's governor Akhichuq and occupied Tabriz, but realized that he could not hold his position against the Jalayirid troops marching from Baghdad and soon retreated.

Shah Shoja proved to be a less of a tyrannic figure, but he was constantly fighting with his brothers, causing a long period of instability.

In the following year however, Shah Mahmud, with the support of his father-in-law Shaikh Uvais of the Jalayirids, invaded Fars and captured Shiraz.

Shah Mahmud would continue to play and influential role in Iranian politics, using his marriage alliance to claim Tabriz from the Jalayirids after Shaikh Uvais died in 1374.

Shah Shoja then marched on Tabriz himself, but was forced to turn back when internal conditions in Fars deteriorated.

Before dying in 1384, he named his son Zain al-Abidin his successor and his third brother 'Imad ad-Din Ahmad as governor of Kirman.

Not satisfied with the arrangement, Shah Yahya advanced against Shiraz, but was expelled from Isfahan by the city's populace and was forced to flee to Yazd.

On his deathbed, Shah Shoja wrote a letter to Timur, who was then campaigning in Azerbaijan, in which he gave his sons' loyalty to the conqueror.

Shah Mansur and 'Imad ad-Din Ahmad, along with other Muzaffarid princes, went to Shiraz to declare their loyalty, whereupon Timur restored them to their positions.