In 656, the Gnomon of Zhou (Zhoubi 周髀) was canonized as one of the Ten Mathematical Classics (Suanjing shishu 算經十書) that would serve as the basis of contemporary curricula, testing and, later, the study of the history of mathematics in ancient China. Itself purporting to have been transmitted from the beginning of human civilization to the Duke of Zhou 周公 (r. 1042–1036 bce), most modern scholars follow Qian Baocong (1968) in positing that the text was redacted from earlier materials circa 100 bce. In this paper, I will present linguistic evidence that supports Christopher Cullen (1996) and early Qian Baocong’s (1924, 1932) position that the received Gnomon of Zhou came together much later, in the first or second century ce, at around the same time or later than the Nine Chapters on Mathematical Procedures (Jiuzhang suanshu 九章算術). In addition, I will present evidence connecting its early reception and transmission history to the Far North/Northwest that might explain features of this strange text and its strange position in discussions of cosmology in the Middle Period Chinese capitals further south.