Son of: Septimius Severus.
Brother of: Caracalla.
Group 1: Group 1: The legends and the portrait correspond to an existing official type.
Group 2: A small mistake like a spear instead of a scepter. The rest of the coin perfectly follows the official coin. Or depreciated coin, but leaving parts showing that the coin seems to have the legends and the portrait corresponding to an existing official type.
Group 3: The existing official type is well imitated but contains one or more errors of legend, representation or degenerate style (excluding hybrid).
Group 4: The coin is a hybrid of two official types (obverse / reverse) and may also include legend errors. Or, the coin is known in another module or metal.
List of types
CASTOR Group 1
P SEPT GETA – CAES PONT
Draped Bust of Geta to the right.
C - A - S - T - O - R
Helmeted Castor (engravor error), standing left and holding a horse behind him by his bridle with right hand. In his left hand, a scepter.
Photos coming from a coin sold by Numismatik Naumann, link to the sale: https://www.acsearch.info/search.html?id=1611279, link to their website: http://www.numismatik-naumann.at/. Information of weight and diameter coming from the coin in picture.
The type imitated is the RIC 6. However, although I classify this coin in group 1; there is a small mistake on the reverse, noted by Numismatik Naumann. Indeed, Castor wears a helmet here. Quote Numismatik Naumann's comments on this subject:
''Castor is usually depicted bare-headed on this type. Despite the forger's ability to imitate the official style of the dies, he inaccurately added a helmet to the depiction.''
PRINC IVVENTVTIS Group 4
P SEPT GET(A?) – CAES PONT
Draped and cuirassed of Geta.
Diadumenian (see coment below) standing facing, head right, holding standard and scepter.
The weight and diameter informations comes from this coin. The A of Geta on the the obverse seem absent. I noted on the reverse that it is Diadumenian because, as Roma Numismatic Limited points out, this coin is a hybrid. The reverse is the one used by Diadumenian in 211, this is the reverse of the RIC 102. No official coin of Geta use this reverse. I quote Roma Numismatic Limited:
''As the reverse type we find on this fourée denarius is first recorded during the years of AD 217-218, when Diadumenian served as Caesar under Macrinus, this forgery must have been made after the reign of Geta.
Interesting Fourée Mule Denarius''