The training of the cavalrymen called Scythian in the 6th book of Ps.-Maurice’s Strategikon consists in the circular movement of the cavalrymen, “when … the right wing is outside, and the left inside”. The main purpose of this movement of cavalrymen is “to enclose an appropriate space” where the supposed enemy stands. But quite strange is the fact that the cavalrymen ride around the enemy in a clockwise direction: in this type of encirclement, the riders will turn to the enemy their right side not protected by the shield. There is a parallel locus in the 3rd book which is a condensed summary of the ‘Scythian’ chapter. There is another similar text in the 12th book, but this time with tactically correct movement of the cavalry, which is counter-clockwise. At the end of the description of this manoeuvre it is written that this manoeuvre is in use among the Scythians. To explain this following construction is proposed: the ‘Scythian’ chapter was first copied to XII D (Phase 1); at that time, perhaps, was the text of the ‘Scythian’ chapter with the yet tactically-correct movement of the cavalry; words ἐσώτερον — ἐξώτερον were changed by their places as a result of the mental error of the copyist (Phase 2a); words τουτέστιν … διῃρημένα and καὶ οὐκέτι … διαιρεῖν were added perhaps as marginalia (Phase 2b); the newly revised text of the ‘Scythian’ chapter became source for III. 5 (Phase 3).