I try to find out, what did the babylonian call the city, what did the assyrian call the city, romans, arabs, orromans, hittites, Vikings (held Kiev, Smolensk, Novogrod, Dublin, York, etc), Greece.
There are many cases where many of them had their own name for a citiy, so if they conquered the city and that city held a significant role for the empire in question, and they had a unique name for it, then I think they should have that city in their city list.
If they didn't have different names then I evaluate which of the civs the city was most significant for, or perhaps "Which civ/empire is most natural to think about when hearing the city name in question.".
The civ that founded the city should be prioritized unless the city was only an insignificant hamlet until it was conquered/rebuilt and then made into a great city by another civ.
I also try to figure out when the name for the city was taken into use and by whom.
I haven't investigated the city of Tarsus, currently it is only in the ottoman city list and I don't think any other civ currently have that city under a different name in their city list.
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The Hittite founded it and called it Tarsa.
The Neo-Assyrians called it Tarsisi, and held the city between 900-625 BC.
The Area was a vassal for the Persian empire between 625-333 BC.
The Greek called it "Antiochia on the Cydnus", but I wouldn't put this name in the game. Many places have held the name antioch:
Link
It was known as Juliopolis by the Romans who held the city for a long time; between 67 BC and 330 and this is the period when the city became significant.
Hard to pinpoint what the Byzantine called it, they officially mostly used Latin place names even though they mostly spoke greek dialects. Held between 330-630, and contested with the Arabs until early 8th century. By 750 the city was lying in ruin. Between 800 and 830 it was once more held by the Byzantine. The Byzantine reconquered it from the Arabs also in the year 965 and held it until 1085.
It held little importance for the Rashidun caliphate (Base for the Arabian empire), they called it Tarsūs as far as I can figure out.
Tarsus history was messy in this period, but it calmed down a bit when the city was held by the Ramazanids between 1359-1516.
The Ottomans claimed the city in 1516.
I can only find three acceptable version of this city, Tarsa for the Hittite, Juliopolis for the old Roman empire, and the modern name Tarsus for the Ottomans.
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I found it fine the way it was.
If someone forced me to pick a change, then I would choose to colorize the entire help text line in perhaps cyan or yellow.