On the easiest difficulty the AI is most likely not going to do well. At all. As I recall that is the only level that actually changes how it works, changing how likely it is to do some things; every other level has the difficulty depend enttirely on bonuses being given to the player and penalties to the AI (below Noble difficulty) or bonuses to the AI and penalties to the player (above Noble difficulty). Noble is relatively even - the AI gets a couple of minor advantages like reduced cost unit upgrades and slightly lower inflation, but the player gets at least one miunor advantage in slightly reduced civic upkeep cost.
On the easiest difficulty the AI needs 60% more food to have its population grow, so it's cities will be much smaller than yours, and it also needs 60% more production to build a building or unit. Meanwhile you are getting a bonus that the research point cost of technologies is only 60% of what the AI has to pay.
The most advanced AI may very well be half an era or more behind you and suffering from terrible production and a bad economy. The AI does not like to expand to new cities when its economy is bad (for some possibly odd definition of "bad" that is built into the DLL for checking this).
I have never actually played below Noble difficulty since I have little to no trouble dealing with the AI at Noble. When playing for testing purposes I used to play at Noble (because it is the closest to even between the player and AI in terms of bonuses) but started to use Prince about half the time quite a while ago. When playing for fun, rather than testing, I usually play at Monarch which sometimes gives me a moderate challenge (so I don't get everything my way, but I'm still very likely to win) and sometimes doesn't. The AI is not as good at playing the game as it is with regular BtS, and it is not incredibly good in BtS - you have to go up at least one difficulty level to have any chance at the same degree of challenge, possibly two levels (it is pretty random - some games they do better than others).
Even if you are new to the game, I suggest not playing R2R below Warlord difficulty (the 3rd one). At that difficulty the player has a small (usually 5% to 10%, but some larger) advantage over the AI in most areas of the game: production cost for buildings & units, research point cost for techs, food required to increase the population of a city, civic upkeep costs, unit upkeep costs, and others. The AI gets slightly less inflation, cheaper unit upgrades, lower unit upkeep costs, and less war weariness (and maybe a couple of other small bonuses ).