According to historian Cemal Kafadar, one of the main reasons for the decline of the devshirme system was that the size of the Janissary corps had to be expanded in order to compensate for the decline in the importance of the sipahi cavalry forces, which itself was a result of changes in early modern warfare (such as the introduction of firearms and increased importance of infantry). Indeed, the Janissary corps would soon become the empire's largest single military corps. As a result, by the late sixteenth century, the devshirme system was increasingly being abandoned for less rigid recruitment methods that allowed Muslims to enter directly into the Janissary corps.