This paper exploits the genre of witness depositions for an examination of the development of periphrastic do in the Early Modern English period. Depositions are speech-related texts, reports of authentic speech events related to a court case. Periphrastic do (in contrast to simple V, i.e., without an auxiliary) is investigated in terms of the parameters of time, and sentence type (affirmative, negative, interrogative, and imperative) against the background of previous research. Further potential linguistic and extra-linguistics factors influencing usage that are taken into account include type of verb, and region. The development in the use of the do-construction across time, and as regards the parameter of region, was found to be generally in line with previous research; however, monosyllabic verbs were found to encourage do-periphrasis, which is in contrast to previous findings.