 Both Sima Qian and modern historians suggest that it was likely compiled from various extant military treatises present in the state of Qi in the fourth century BC, in the mid-late Warring States period.If "the Methods of the Sima" was compiled from other pre-existent military writings, the origin of its component texts cannot be known with certainty.Presently, because only five of the 155 chapters reported in the Han dynasty exist, all editions of "the Methods of the Sima" seem to be remnants of a larger, more extensive work.