RomanArmyTalk

I have read more than one article recently discussing the fate of the Ninth Legion. The articles all cite to CIL VI 3492. (i.e. the inscription with the list of 33 Roman Legions) as offering proof (along with Dio) that the Legion had ceased to exist by the reign of Marcus Aurelius. I located a photo of the inscription, however, and noticed that it clearly includes I, II, and III Par(thica). Since those three legions were raised by Severus, why do the authors of the articles believe that the inscription dates from the earlier reign of Marcus Aurelius?

Thanks in advance for responding to my query.

P.S. I also saw a reference to a work by Emil Ritterling, where he supposedly posits that the inscription dates from the reign of Antoninus Pius.

The reason is that the legions are listed in geographic order except for the II & III Italica and I- III Parthica, so these are believed to have been later additions simply added at the end of the text.