This beautiful specimen has been photographed just like most specimens are. This orientation of the reverse is necessary to have it match Crawford’s description, ‘Horseman galloping, r., with r. hand dragging naked warrior, who holds shield in l. hand and sword in r. hand.” The difficulty with the photography and this description is that it ignores the ground line. Here’s the same image slightly rotated.
The warrior is kneeling. He may be wearing pants. He’s clearly a ‘long haired barbarian’. The horse is rearing. And, the most likely interpretation of the scene is that the barbarian is stabbing the horse. If you remember from a couple of posts ago, having two horses cut out from under him (and living to fight on) was part of the heroic career of Sergius. Facing horse stabbing enemies is part of the motif of the brave Roman warrior. And, it shows up in artistic representations left right and center. I don’t have to collect the information because one military historian, Prof. Michael P. Speidel (University of Hawaii – nice work if you can get it!), has collected a whole chapter’s worth of examples. I kid you not, chapter 17 of his book, Ancient Germanic Warriors (Routledge 2004) is called ‘Horse Stabbers’. While his presentation of the evidence is strictly non-chronological and I don’t always agree with his interpretation of the evidence, he cites all his primary sources and does a fine job of making clear that Romans (and the Greeks) thought a horse stabber was a very scary thing indeed.
Does this help with answering which heroic ancestor this was? Not particularly. But Brennan, Praetorship (2000) 228, 246, esp. n. 38 and 39 on p. 344, relies on Obsequens 22 and Frontinus Str. 2.5.28 to suggest that Licinius Nerva the Macedonian Praetor of c. 142 (Liv. Per. 53, Var. R. 2.4.1-2 and Eutrop. 4.15) was engaged in difficult combat with the Scordisi and perhaps the Iapydes on the Northern frontier of his province.