Seems like the "Chariot Clan" in CIV6 are basically the ancient Indoeuropean peoples, then what about this:
> "Chariot People" aka Indoeuropeans. Start with Horse resource and Wheel technology.
- HITTITE (eureka for Smelting technology)
- YUEZHI (produce a Camel resource)
- THRACIAN (provide Peltast unit)
- SCYTHIAN (grants a copy of cavalry units)
- CELTIC (construct Oppidum insfrastructure)
Let's see if we can refine this a bit.
Good news, it all fits within the 'traditional' Civ start date of 4000 BCE.
At the moment, the earliest identified proto-Indo-European speakers are the
Yamnaya Culture, dated back to 3400 - 2600 BCE. They herded sheep and cattle from horseback, hauled their worldly goods in solid wheeled wagons drawn by horses or oxen, had pottery, gold and silver ornaments and built Kurgans. BUT they did not fight from horseback, having no weapons hat were adapted for it: javelins, copper/stone axes seem to have been their primary weapons and men on foot could use them better than a man on a horse with no decent saddle or tack yet.
Humankind's Scout Rider unit is actually a very good representation of this - really fast scouts with really mediocre combat factors.
Flash forward about 500 years, and from 2100 - 1800 BCE the
Sintashta Culture shows up in the same area as the earlier Yamnaya - north of the Caspian Sea on the central Eurasian steppe. Still got the wagons, the herds of sheep and cattle, the kurgan building, but much more evidence of inter-tribal/group warfare: they had short bows that they could apparently use from horseback (but not true composite bows until possibly the very end of their period) and fortified villages. In their kurgan burials are also found the very first spoked-wheel
Chariots.
That technology spread remarkably fast:
1700 BCE - chariots and composite bows in Shang Dynasty China
1650 BCE - chariots and composite bows introduced into Egypt by the Hyksos
1600 BCE - spoked wheel chariots in Mycenean Greece
1500 BCE - spoked wheel chariots used by the Mitanni in Mesopotamia
1300 BCE - chariots depicted in Spain, Germany, Poland and Sweden - meaning the technology is pretty much general throughout Europe
Except in Italy - here is no indication that anyone south of the Alps had chariots until much, much later - in fact, most of the Latin words relating to chariot, wagon or cart technologies have Gaulic roots, meaning that the entire technology may have been 'borrowed' along with the words from the Celts to the north almost 1000 years after the rest of Europe had it.
Now, the earliest "historical" (mostly in other people's 'histories' rather than their own) charioteers are a little different, and if we don't want to intrude on potential Civilizations for the game (that is, groups with identifiable named Leaders) here is possibly a better list:
SHANG (eureka for Bronze Working technology)
MITANNI (provides an automatic Horse resource)
HYKSOS (produces Chariot Archers)
CIMMERIAN (provides a Horse Archer unit)
CELTS (construct
Oppidum Improvements)