Themistius orationes IV-V-VII-IX-X are transmitted by the MS tradition in this succession and appears to have been a corpusculum of late antique origin. The text of or. IV has been collated in all the extant witnesses (twenty in number); a selective collation has been carried on for orr. V-VII-IX-X. A description of the medieval manuscripts is provided and their relationships are established. All the Renaissance MSS (twelve in number) are demonstrated to derive from a lost ancestor (Ω). Hence a stemma codicum is drawn, where the medieval MSS and omega find their place.