An increasing body of studies point to supralocalisation processes being an important factor in the emergence and development of written Standard English, which largely took place from the Late Middle English to the Late Modern English period (c. 1400–1700). Given that the south-east area, with its metropolis London, played an important role in this development, it is not surprising that this region has received much attention by English historical linguists and philologists. The current paper shifts the focus to written English in the important regional centres of York (North), Bristol (Southwest), and Coventry (West Midlands) in the same period to explore potential supralocalisation processes, which in turn help to further our understanding of the underlying standardisation processes of written English. Couched within the field of historical (socio)linguistics and based on new manuscript material from these urban centres, this paper combines qualitative and quantitative approaches with the philological method to present new findings on the development of periphrastic DO, paying particular attention to the language-external factors place and text type. The results, in line with previous studies, reveal that periphrastic DO primarily occurs in affrimative declaratives and to a lesser extent in negative sentences in all investigated text types in the different urban centres over the period 1400–1700. However, in contrast to earlier findings, no clear rise-fall pattern emerges, and it is diffcult to determine a path of supralocalisation.