Meanwhile, Nader & Tahmasp had been campaigning in the north-east building up a base from which to challenge Ashraf's claim on his newly acquired dominion. Hearing of the Nader's march on Herat, Ashraf set out from Isfahan in August 1729 with a host 30,000 strong, in the hope of conquering Khorasan while Nader was waging war on the Abdali Afghans further to the east. Unfortunately for Ashraf, Nader subjugated Herat and returned to Mashad before Ashraf could invade Khorasan. Upon hearing of Ashraf's approach Nader gathered his fighting men to set out via Sabzevar on September 12, 1729.