In this paper, we focus on the diachronic development of the distribution of adverbs with respect to modals. The history of modals in English has played a very prominent role in the literature in diachronic generative syntax over the last forty years (cf. Lightfoot 1979 and much subsequent work). By examining the distribution of modals with respect to adverbs, we will provide new empirical evidence to evaluate proposals that have been made with respect to the historical development of modals in the earlier literature. There is a general consensus that modals underwent a reanalysis at the beginning of the Early Modern English (EModE) period, which changed their categorial status from lexical to functional. Accounts differ with respect to whether this recategorization involved a radical change from V to T or whether this transition was less abrupt in that modals were already categorially distinct in some way as compared to regular main verbs before they became purely functional items. These two options make somewhat different predictions with respect to adverb placement. Presenting quantitative data concerning verb movement and, more specifically, the distribution of finite main verbs and finite modals with respect to adverbs from Old English (OE) to EModE, we will show that, while the behaviour of the two types of elements up to the reanalysis of the modals is not entirely identical, their overall diachronic development is. Given furthermore that the observed differences can be accounted for independently of a categorial distinction, we conclude that adverb placement does not provide any evidence against the hypothesis that modals and main verbs are categorially identical in the early history of English. Finally, our data will provide new evidence for the dating of the reanalysis of the modals and confirm proposals that have been made in the earlier literature.