Abstract One of the signs of the early implementation of shared bureaucratic practices across the newly established Islamic empire are the highly standardized formulaic features of seventh- and eighth-century Arabic official documents. At the same time, the use of dates and dating formulae appears to have been less closely regimented compared to other components of Arabic documentary templates. This article offers an overview of the different dating formulae used in the early Islamic official correspondence with an emphasis on patterns of difference (e. g., how norms for date formulations varied depending not only on the function of the document but also on the issuing office, scribe, recipient, direction of the communication). In particular, it is argued that the comparatively high variability of dating formulae suggests that the dates were not considered to be a structural part of documentary templates and were therefore more prone to respond to social variables, such as corporate designs of single chanceries and scribal styles. Furthermore, evidence suggests that dating formulae (or the absence of a date) reflect the register of written communication.