Few issues have had as far-reaching consequences as the development of the Christian holy day, Sunday. Every seven days, from the early middle ages, the Christian world has engaged in some kind of change in behaviour, ranging from participation in a simple worship service to the cessation of every activity which could conceivably be construed as work. An important text associated with this process is the so-called Sunday Letter, fabricated as a letter from Christ which dropped out of heaven. In spite of its obviously spurious nature, it was widely read and copied, and translated into nearly every vernacular language. In particular, several, apparently independent, translations were made into Old English. Here, the six surviving Old English copies of the Sunday Letter are edited together for the first time. The Old English texts are accompanied by facing translations, with commentary and glossary, while the introduction examines the development of Sunday observance in the early middle ages and sets the texts in their historical, legal and theological contexts.The many Latin versions of the Sunday Letter are also delineated, including a newly discovered and edited source for two of the Old English texts. Dorothy Haines gained her PhD from the University of Toronto, where she is currently an instructor of Old English.