From a Classical Numismatics Discussion post by Hans-Joachim Hoeft (Jochen).
I think each of you concerned with provincial coins has come across
these types were priests leading a pair of oxen. Here is a closer view
at this archaic Roman custom.
Macedonia, Philippi(?), Tiberius, AD 14-37
AE 17 (semis), 3.41g
Obverse: [TI] AVG, Bare head right.
Reverse: Two priests in long garment, veiled, behind pair of oxes, plowing the sulcus primigenius.
Reference: RPC 1657
rare, VF, nice green patina
BMC Mysia locates this type to Parium in Mysia, but more recent found hoards indicate for a European origin.
The custom of the sulcus primigenius
was looked at by the Romans themselves as very old. Already Romulus has
performed this rite and in this way founded Rome. Dionysos von
Halicarnassus (Ant. Rom. 1. 88) suggests that this act of Romulus has
served as example for the foundation of all later Roman cities. An
incomplete list of colonies using this reverse type includes:
● Brundisium
● Philippi
● Caesarea Maritima
● Caesaraugusta
● Akko-Ptolemais
● Ninica
Claudiopolis
● Berytos
● Petra
● Rhesaena
● Antiochia
Gaebler
describes the practice based on coin pictures and the description of
Hyginus Gromaticus: The act of founding the colony has been done in this
way: When the colones have arrived and the auspices have been obtained,
the legatus coloniae deducendae, with his toga worn in a special way (ritu Gabino), part of it covering his head and part of it tied around the waist as belt, plowed around the area which was provided for distribution a furrow (sulcus primigenius).
This was done counterclockwise with a dyad which has to be on the right
side (outwards) a bull and on the left side a cow. In doing so they
held the bent handle of the plow so that the clod fell inwards. At
that places were later should be the gates they lifted the plow so
that the furrow here was interrupted (Varro LL.5.143).
Already previously the territory has been measured by agrimensores (surveyors) and divided in square areas (centuriae) and these further segmented in a certain number (sortes acceptae).
Now the distribution of land began. This was done - as we know by the
writings of the gromatic Hyginus - by lot and in three stages: at first
the candidates were arranged in decuriae or in conternationes (10 or 3 recipients per centuria), then the order in which this community (consortia) should draw the lots, and not before this was managed the actual drawing of lots sortitio centuriarum has occurred.The legatus then has taken place on the sella curulis
and before his feet the urn of lots has stood. From this urn the lots
(probably small inscribed wooden rods) were drawn and everyone assigned
his piece of land.
The ritual act of the founding therefore has consisted of two equal important procedures: the defining of the area by the primigenius sulcus, which confirms the connection to the ager publicus populi Romani, and the distribution of the field lots by the legate (sortitio).
The sulcus primigenius
enclosed the sacred part of the city and itself was sacred too.
Romulus murdered Remus because Remus jumped over the sulcus primigenius
he plowed for the foundation of Rome. To what extent the pomerium was identical with the
area enclosed by the sulcus primigenius is a problem not
definitely solved by the scholars. In any case the pomerium has to be
seen as a region of order in contrast to the surrounding wilderness, in
in this way too as dominance over the environment.
The Romans probably adopted this rite - as so much - from the Etruscans.
This rite may been repeated annually at some cities by the local
priests.
Notes:
Gabinus, after the city of Gabii, east of Rome.
gromaticus - surveyor (named after a measuring device).
cinctus Gabinus: In
early times, when the toga was the only garment of the Romans in peace
and war, in a battle it was looped around the body as bulge (similar to what the Greeks did with their himation), therefore classis procincta
= the army. In this garb Mars was depicted on coins or statues still in
imperial times. The cinctus
Gabinus is a special form of this girdling: the bulge was thrown over the left shoulder and the girdled
around the waist; it was left for a set of sacrifices (i.e. opening of
the temple of Janus, offering the spolia opima, and so on). The cinctus Gabinus did not cover the head, therefore the reading - more often survived in Hss. of Serv. Aen. 5, 755 - ritu Sabino deserves preference compared to Gabino. His explanation doesn't satisfy but a more convincing explanation is missing.
I have added the pic of a coin where Mars is shown wearing the mentioned garb.