This paper will address the seemingly simple question of what literate Early Modern Muslims knew, or thought they knew, about the wider world in which the lands of Islam were situated. The early 16th century Khatay'namah, a Transoxanian merchant's description of law and governance in Ming China, contains what may be described as vernacular macrohistory: a narrative of historical developments that took place over many centuries and spanned large portions of the inhabited world, and which does not rely primarily on other written histories as sources. The Khatay'namah and other contemporaneous texts will be juxtaposed with modern macrohistorical scholarship or “big history” of the zone of contact between China and the Islamic world in order to understand the scope and nature of events on which these texts' vernacular macrohistorical narratives were based, thus moving us closer to a thickly described account of actual macrohistorical developments. In the case of the Khatay'namah, the alternative to written history was a combination of oral tradition or widely-known myths, recent reports by other travelers, and first-hand observations. The author of this text combined diverse details, such as the presence of grotesque figures in statues or reliefs in Inner Asian cities reminiscent of the dog-headed and bird-headed people said to have been confronted by Alexander the Great, as well as what appear to be reports of recent demographic changes in Chinese frontier provinces from other travelers or Muslim Chinese, into a narrative of Chinese history from its founding in distant antiquity by the descendents of Cain until the author's present (the early sixteenth century). This historical narrative is rationalistic, attempting to explain China's prosperity and strength in terms of causes and their effects. The Khatay'namah shares this macrohistorical dimension with apocalypses and other texts that may be described as social cosmographies—texts which define the boundaries of the possible in their authors' own social worlds by elaborating conditions comparable to paradise or hell. Apocalyptic legends, in particular, played an important part in political developments in the Islamic world during the fifteenth and sixteenth centuries. By exploring the connection between vernacular macrohistory and awareness of actual macrohistorical developments, I hope to give greater historical specificity to narratives based on theories such as world systems and world culture.