Constantius II (337-361), Siliqua, 3,00 gram and 19 mm. RIC 261 and 291 I have shown that before, so nothing new here. The mintplace says "S CON". I am just wondering: Arles was once named something like "Constantia"(correct me), and thus many have confused this coin to be minted in Constantinople. I am just wondering: how do you know that this coin of mine was minted in Arles(which back then had a name something like "Constantia"), and not in the legendary famous Constantinople? How do you distinguish Arles-minted and Constantinople-minted when they both have "CON" on it? Thanks for any help that may come.
Well, there's degrees of certainty to be sure. There's no 100% factual guarantee that it was minted in Arles (or even by Constantius II for that matter) but it's reasonably certain. Constantinople, and other cities in the Eastern half of the empire, spoke Greek as a primary language. While the coins during this time featured Latin legends one small area where Greek was permitted were to mark the mint's officina. 4th-6th century silver and copper coins coming from Constantinople would take the form CONx where x stood for any Greek letter which in turn corresponded with the officina number so that A=1, B=2, Γ=3 and so on. The western cities with mints however used Latin throughout, including the numerals. In the case of Arles in particular the format used was xCON where the x this time stands for the first letter of the ordinal, rather than numerical so that we get the sequence Prima, Secunda, Tertia and Quarta (Latin for first, second, third and fourth) Hope this helps!
I believe you will find that the city name was changed to Constantina in honor of the then powerful Constantine II but the name was changed back after he died. Unfortunately the CON abbreviation does not make it clear that the name included the N and that the name honored the wrong brother. Politics is particularly difficult when the opponent you killed was your brother and all of you had names starting with CONSTAN.
The only coin in my collection from this mint that is nice enough to photograph is this one: Constantine I, AD 307-337. Roman billon reduced centenionalis, 2.44 g, 17.4 mm, 12 h. Constantina/Arles, AD 331-332. Obv: VRBS ROMA, helmeted bust of Roma, left, wearing imperial robes. Rev: Lupa Romana, left, suckling Romulus and Remus; branch between two stars above; SCONST in exergue. Refs: RIC vii p. 273, 368; RCV 16497; LRBC I 371; Cohen 17.
The letters say "CONSTANTIVS". So why do you say you cannot guarantee that it was minted under Constantius II? - The silver coins looked different under his grandfather (Constantius I), so that coin cannot be minted under the grandfather of same name. Edit: or perhaps you meant Constantine II minted coins on the name of Constantius II ?
I think as a general rule, on bronze coins from Constantia the officina letter precedes the mint city letters (usually CON), while at Constantinople it follows them (CONS). So a coin from Constantia would show something like PCON and one from Constantinople during this same period would be CONSA. But there may many exceptions, so this shouldn't be considered an absolute rule, just a general starting point. But this, plus the Latin/Greek difference pointed out by Suarez (is that you, Rasiel?) should offer some degree of certainty.