The introduction by M. Cecilia Gaposchkin and Sean L. Field provides background information on Louis IX and his two biographers, analysis of the historical context of the 1270s, and a thematic introduction to the texts. An appendix traces their manuscript and early printing histories. The Sanctity of Louis IX also features translations of Boniface VIII’s bull canonizing Louis and of three shorter letters associated with the earliest push for his canonization. It also contains the most detailed analysis of these texts, their authors, and their manuscript traditions currently available.