Abstract: In the age of Chinese medieval manuscript culture, the title, content, and authorship of a text are highly fluid. Through analyzing poems by Xiao Gang (503-551), Xu Gan (170-217) and Cao Cao (155-220) as preserved in the sixth-century poetic anthologyYutaixinyong(New Songs of the Jade Terrace), this article discusses how the sources of medieval texts negotiate with authorship attribution and textual variants, acting as crucial factors in the writing of literary history. The article calls for a historicist reading of medieval Chinese literature, which requires careful examination of sources as well as close reading of texts, hence averting anachronistic interpretations of medieval literature.