In this article we offer a diachronic analysis of simultaneity subordinator as against the background of simultaneity subordinators while, whilst, when from 1650 to the end of the twentieth century. The present survey makes use of data extracted from the British English component of ARCHER (version 3.1), focusing in particular on fiction, the register par excellence for the use of simultaneity subordinators. We analyse our data according to a selection of parameters (ordering, verb type, duration, tense and aspect, subject identity, simultaneity type) and show that, against a background of relative stability, the major change is a dramatic increase in the frequency of simultaneity as-clauses from the first half of the nineteenth century onwards. Adapting the historical work on stylistic change by Biber and Finegan (1989, 1997), as well as theoretical and experimental accounts of the semantics of English simultaneity markers, we highlight an interesting parallelism between the spread of as-clauses in oral narrative from childhood to adulthood and the spread of as-clauses in modern fiction. In either case, the spread of as may be symptomatic of an evolution in narrative techniques, particularly in respect of the means by which complex events are typically represented.