I showed you that government type map before (link), but I never actually explained how I got the government types for each province. Part of making this blog was as a resource for anyone who actually wanted to make an insane timeline extension mod, so I guess it's time to show off my research.

1. Ck2 Government Ids
2. Ck2 Change Government Cheat
3. Change Government Ck2

Crusader Kings 2 Setgovernment Command This command changes the government type of the character with the specified ID. Note that if you change your government type to one from a DLC that isn't installed, the game will end.

• Crusader Kings II - game update v.1.05 - Download Game update (patch) to Crusader Kings II, a(n) strategy game, v.1.05, added on Thursday, April 19, 2012. File type Game update.
• Ck2 tribal to feudal guide When you convert to feudal all the tribes you personally own will be upgraded to castles even if they lack a stone fort. The Caliphate to the south would not dare entrench themselves in a war against a whole empire so I was safe to scheme from within.

The 'wealth' of a province, in this blog post, refers to the maximum number of holdings that it can host.
Civilisations
The first layer of the map, so to speak, was that of the major civilisations existing at the time, which were unfortunately quite sparse. I used Geacron to find the boundaries and names of the civilisations which were around, which number four:
In addition, I considered one more civilisation, which Geacron didn't mark the boundaries of but still existed at the time, in an early form:
I then marked these by their government types. Minoa, Egypt and Ebla were monarchies.
Yes, I know that the Pharaoh of Egypt is considered to be an incarnation of the sun god, and therefore it's technically a theocracy. No, I don't care, it doesn't count because the ruler wasn't appointed from the extant clergy.
Sumer, on the other hand, is a theocracy, as attested to on both Wikipedia and John Green's Crash Course World History Ancient Mesopotamia. It's ruled by an ensi, which is a type of priest, and later becomes a monarchy but not right now. Fast and loose.
The Indus Valley is still a chiefdom because it's not marked on Geacron yet. Faster and looser.
Uninhabited
The next layer of the map is that of the uninhabited islands. This was the easiest part of the research by far, since it was basically going on the list of countries and islands by first human settlement then crossing off anything after 3000 BC. This gives the following areas left uninhabited

Ck2 Government Ids

Socotra is also marked as uninhabited, but this is a mistake - its government form should be hunter-gatherers.
Hunters and Gatherers

Ck2 Change Government Cheat

Change Government Ck2

Any province not featured as having adopted agriculture by 3800 BC or copperworking by 2000 BC on these maps is automatically marked as being of the Hunter-Gatherer government type, unless the province is in Africa, in which case it is of the Nomad government type, unless the province is in Nubia and does not have a high wealth or if the province is in Mali.
If the province is in a region that adopted agriculture between 4300 and 3800 BC, then it is a hunter-gatherer if the province has a low wealth, otherwise it is tribal.
Tribes and Chiefdoms
Any province that isn't hunter-gatherer, and hasn't already been designated, is either tribal or a chiefdom. Everywhere east of the map, but south of the Caspian and/or the Ganges is tribal, save for the Indus Valley civilisation, which is a chiefdom.

Otherwise, the tribe/chiefdom distinction is made depending on the wealth of the province, with the threshold of wealth needed to be a chiefdom decreasing as copper was adopted earlier.