The aim of this brief chapter is to sketch a possible periodization of stages in the diachronic development of Turkic. This is admittedly an almost impossible task since all older stages are insufficiently known and written sources, where available, do not provide reliable information on spoken varieties. One reason for the difficulty to define crucial diachronic limits is the fact that developments in various linguistic domains, i.e. phonology, morphology, lexicon, and syntax, are not congruent, but occur at different speeds. Lack of data makes it hard to specify approximate dates for changes, i.e. the earliest and latest points in time for the emergence or disappearance of a given feature, the terminus post quem ‘the limit after which’) and the terminus ante quem ‘the limit before which’. Nonetheless, linguistic periodization is a favorite hobby of many Turcologists since it allows their imagination to fly around relatively freely.