Having finished the Fire Making technology, I research Cooking, then Carpentry. I'm still researching a lot of basic stuff.
At this point, I finish training a Thief to start exploring again. I lost my Wanderer to a Hyena, and a Scout and a Tracker to Neanderthals. Unlike these units, the Thief is invisible. The Thief cannot enter an occupied square unless it wins a fight, and with only a strength of 2, it won't be doing that very much. However, the animals and Neanderthals can enter the Thief's square without fighting it. Other Thief-type units and Animal units may be able to detect the Thief, and if any of them can see it, other units can attack it. It's more dangerous to use a Thief to enter another civilization's land. The Thief has Hidden Nationality, so it can enter borders without a Right of Passage/Open Borders agreement and can be attacked even if its owner is not at war.
I train a few more Slingers as I discover Tribalism. Tribalism is the big midpoint of the Prehistoric Era, because you can build a Tribe unit. The Tribe is the early version of the Settler, and lets you found a new city. The only problems with the Tribe are it is very expensive for the era, and it is a National Unit with a limit of 1. Once you build a Tribe, it has to found a new city before you can even start building another Tribe. I put off actually building a Tribe just yetthey are pretty expensive.
After Tribalism comes Bone Working, followed by Personal Adornment. While I research Personal Adornment, I get the Most Advanced display and I am 7th. I still don't worry.
I love this dotmap feature. It lets me put down dots that show the locations and tiles for future cities. I mark several locations that I think would be useful, especially near the rivers to the west.
My wandering Thief comes across Portuguese land. Now I know where an enemy is. It also means I want to expand north and west to check Gilgamesh's expansion.
One thing about this particular terrain palette is that certain civilization colors are very hard to see against the landscape. If I wasn't already a yellow civilization, I would use the BUG mod to set my civ's color to a yellow to make it easy to see.
I finish Personal Adornment. This is its short name. Its proper name is "Death to All Neanderthals Everywhere". This is because I can now build Rogues. Rogues are like Thieves, but Strength 3 and 1 first strike. With a little help from suicide Scouts and distraction from other Rogues and Thieves to get their first promotions, these guys become Neanderthal-killing machines.
I research Spear Making, then Sewing.
My Thief gets far enough into Portugal to locate Lisbon.
My first Rogue is done, so now I start training a Tribe. I am looking west, towards the mouth of the nearby river.
Gilgamesh gets a Great Prophet. This is because he is the first to discover Naturopathy. Unlike vanilla Civ4, Caveman to Cosmos currently has TWENTY-SIX religions. I have Divine Prophets on, so each advance that normally triggers the founding of a religion instead spawns a Great Prophet. Great Prophets can spread any religion that you have the technology for into any of your cities. The first city to get a particular religion becomes the holy city. This can lead to what is known sometimes as Jerusalem Syndrome--founding many religions in one city.
Gilgamesh uses his Great Prophet to found Druidic Traditions (which is keyed to Naturopathy) in Lisbon. The first three religions in the gameDruidic Traditions, Shamanism (keyed to the Shamanism tech), and Ngaiism (a South African religion, keyed to Livestock Domestication) automatically spread to every capital on founding. This helps if you can't found a religion of your own. I also have Religion Decay turned on. Religions that are not popular (not your state religion, no buildings, etc.) may decay and disappear from your cities. (The other way to get rid of a religion is through an Inquisition. I haven't actually ever needed to do that).
I can't convert to Druidic Traditions yet. I'm in Folklore right now, which isn't religiously advanced enough to have a state religion. The civics of Prophets and Divine Cult (at Mysticism) will allow that.
Coming next: The first March of the Inca.