Chapter 2 treats the Southern Middle English backing and rounding (and briefly the subsequent raising and diphthongisation) of the reflex of OE ā, which is believed to have started in early ME and to have been completed by 1225-1250; the further raising and diphthongisation took place in the early Modern period. The spelling evidence implies that the change in fact started in the eleventh century, and had not been completed across the affected area until the fifteenth century; it therefore partly overlaps with the GVS, even as traditionally defined. The shift may have been combinative, since early forms are found first in the vicinity of [w] and [n]. It is also possible that the shift was a ‘prelude’ to the GVS, or indeed one of the earliest stages of the shift proper.