Nader had had to cancel his planned invasion of Ottoman held Caucasus territory in light of the fact that the Abdali Afghans had rebelled and invaded Khorasan, besieging its provincial capital Mashad.

Tahmasp II who sat observantly on the newly regained throne (which he owed to Nader) was cajoled by his courtiers into taking to the field himself.

Although Michael Axworthy and many other historians accuse Tahmasp of being motivated primarily by jealousies caused by his illustrious commander-in-chief's incessant victories there is reason to suspect his decision was in fact induced by court intrigue amongst the imperial entourage eager to have their Shah outshine Nader and thereby lessen his influence.

Hearing of Ahmad Pasha entering west Persia with the intention of taking Kermanshah and Hamadan, Tahmasp was now caught in a dire situation.

The Persian army was largely composed of raw recruits (the veterans campaigning far in the east under Nader) and was formed up in the traditional manner of three divisions making up the centre and the flanks.