 A century later, Duke Jing of Qi (r.547-490) reportedly used the work in his successful effort to retake land previously lost to Qin, and to subjugate several other feudal lords.According to this theory, the texts used by these rulers were all gathered and compiled during the reign of King Wei of Qi, and the resulting book came to be known as the "Methods of the Sima".There are other historical writers associated with Chinese military classics whose writings may have contributed to the "Methods of the Sima".