First, these are not my coins - I'm only using them for reference. The portrait bust of Vitellius in the center photo is well known and accepted as being accurate. However, almost every Vitellius coin I've ever seen has the obverse portrait on the right, which looks nothing like his portrait bust and can't be the same person portrayed in the sculpture - no resemblence at all, not even close. The coin on the left, by contrast, looks almost exactly like the portrait bust, with the same proportions, head shape, face, etc, and so must be the same person as the one depicted in the sculpture - in other words, the real Vitellius. Even if the coin on the left were disregarded, the portrait bust and the coin on the right are vastly different. My question, then: whose portrait is on so many Vitellius coins (such as on the coin on the right), and how could someone who looked so unlike Vitellius have been put on so many of his coins?
The coin on the right was minted in Rome after Vitellius arrived in the city and consolidated his position. The coin on the left IIRC was minted in Hispania or Gaul, where he never set foot during his tenure as Augustus. The leading theory is that mints used busts of the emperor to model the obverse portrait, and it is quite possible that the one used for the left coin was a decade or two old. The statue in the middle is Vitellius, but we have no way of knowing whether that statue was made while he was Augustus in 69, or a decade or two earlier, as it was pretty common practice for the new emperor to destroy the image of the old one.
The coin portraits are labelled as Vitellius. The famous “Grimani Vitellius” bust is not. It has traditionally been attributed as Vitellius, but no one knows for certain. There is even doubt that it's Roman and may possibly be a Renaissance fabrication. I'd stick with the coins despite their many variances.
I'm going to go with the coin on the right being the real portrait of Vitellius, then, if it was minted after he had already been in Rome for a while. You can't beat a living breathing reference. If the die engravers in Spain had never seen Vitellius, all they had to go by was whatever bust or busts they were told were him. I don't think age explains the difference in these two specific coins...age can only change someone so much, but age doesn't change a head from a tall square one to a short round one.
Like Finn says here, you will often notice that there may be great variation of the portraits, especially early in the rule of an emperor, or if it was a mint where the emperor had not set foot. Maximinus never set foot in Rome while being emperor, so early portraits of him look like completely different people.
If you wanna know the truth about Vitellius, here is a good link : https://uncyclopedia.ca/wiki/Year_of_the_Four_Emperors
