G. E. F. Chilver and Gavin B. Townend (eds), A Historical Commentary on Tacitus' Histories IV and V
1. praetorianam militiam, II. 67. 2 n., 93. 4, III. 55. 2, with Wellesley, III, Appendix, 220. There were three groups claiming service in the Guard: (a) members of the Othonian cohorts dismissed by Vitellius and called, with some exaggeration, robur Flavianarum partium at II. 67. 4; (b) what remained of Vitellius' sixteen cohorts, composed of men from his legions and even from the auxilia, II. 93. 9 n., but perhaps including some of the earlier praetorians; (c) men from Antonius' legions who had been promised service in the Guard, as described here. Fabia's article, Rev. Phil. 1914, 32 ff., is still useful. Mucianus chose some from all these groups (for Vitellians see ILS 2034–5 = MW 275, 381), and it was clearly a considerable feat that the guard was gradually reduced to nine cohorts (diploma of ad 76, ILS 1993 = MW 400).
12. aliorum exercituum. It is not clear what other troops were still in Rome, nor what armies they came from, unless there were still some pg 58men from the detachments listed in I. 6. 11. Fabia, op. cit. 71, despairs of a solution.
25. isque finis ilia die. Fabia, op cit. 73, maintained that at this point Mucianus changed his mind about the Vitellians; but falso timori obviam iret suggests that he staged the scene just described in order to bring the Vitellians into a proper state of mind.