This paper focuses on the relation between version α of the seventh book of Aristotle’s Physics and the two byzantine families which shape the transmission lineage of most Aristotelian texts. To this end, it establishes a stemma codicum of all known manuscripts of version α. The first step reexamines Simplicius’ testimony in order to overcome the stemmatic problem arising from it: Simplicius’ statement that there was a version β for chapters 4 and 5 seems to be mere speculation on his (...) part. This allows for the more plausible assumption that only the first three chapters of book VII were transmitted in two versions. The paper then deals with the witnesses of version α, which either transmit version α as a whole or a mixture of the two versions. H and I are shown to stem from the same manuscript ι. ι was used by E2, who famously annotated Paris. 1853 and copied in its margins scholia derived from Philoponus’ commentary as well as κεφάλαια of book VII, both of which also feature in manuscripts close to H and I. Though ι is the source of both a version α and a version β, the original version of manuscript ι was βι. Therefore, version α cannot be associated with certainty to either of the two byzantine families of Aristotle’s natural works. Although version α may come from a now extinct third family, there is no trace of such a family in either Paris. 1859 or Vind. 64, which both got the text of book VII from the same manuscript φ. In any case, the evidence points to all direct witnesses of version α coming from only two sources: ι and φ. (shrink)