There were tested 2,000 Ujjaini Rajputs led by Raja Gajpati of Bhojpur in the army of Sher Shah at the battle of Surajgarh in 1534 against the invading Bengal army led by Ibrahim Khan and Jalal Khan (Bihar through ages, p-479). Battle of Surajgarh was turning point in the career of Sher Khan, he became defacto ruler of Bihar after it. After the battle, Raja Gajpati was allowed to retain the war booty captured from the Bengal army and Sher Khan presented to him bejeweled sword, armlet, and a string of pearls. Also Buxar was conferred on Gajpati as Jagir by Sher Khan. (proceedings of Indian history congress, 1922, p-352)
Gajapati was extremely obliged to Sher Khan for the help given to him by Sher Khan in wresting the Bhojpur throne from Shivaram Singh Ujjainia (his uncle) in 1533.
It is reported that Sher Khan, presumably after he had become Sultan, conferred the title of Raja and the districts of Rohtas and Shahabad on Gajpati. (Imperial gazetteer of India, XI, p-378)