I don't know if it has been done yet (and i know it is not the main objective of the game), but I wanted to see if a world conquest was possible!
I am abandoning the game now, so I thought I share what I had accomplished. The reason i'm abandoning the game is two fold.... The first and most important reason is the time each turn takes... upward to an hour. I just don't have the time for another 300 turns
Second, when I opened up the save I saw that some stuff had changed and I am running a deficit now, while a few weeks ago (when i'd played last) I was running a 10k surplus.... I don't really feel like investing the time into fixing it (which is certainly possible, that I know). So that's the failure part... I didn't actually do a proper WC...but i could have... 
I chose Judea with two specific reasons.. one, to start out small so as to make it an uphill battle from turn 1... Picking Rome would have been easier and quicker, but I wanted to see if a small nation could pull it off. Second, Judea is the only nation which can repair Solomons Temple, and I wanted to have all the world wonders in their splendor, not a crumbling ruin! Also the Temple is imho the key to success for a WC. The reduction in chance to gain a minus token is what has kept me from regressing for over 150 turns... I'm even a Glorious Nation which i got while in the bottom tier, just by conquering objectives!
Some screenshots...
The Empire in turn 281. I'm in a few minor wars and would have started on Rome if i had continued. They are the only real nation left, but they too would have been a pushover.. My army is four times their size, my navy ten times and they are on the brink of a civil war. I had opted to let Plotemaic Egypt live after kicking them out of the Nile Delta, since they can't raid me and they pose no threat in the barren desert of Africa. In general opponents weren't the real enemy, terrain was! Slogging it out in Mountain regions is what took the most time and frustration. It is the only place where Economy and Quantity don't matter
... My solution was attacks with only Hvy Cav and Skirmisher Cav. That usually did the trick...
Overview Panel. Leading in Legacy after about 200 turns. Over 7000 pop, about 70 Provinces (377 regions total). I use to have a suplus of 10k gold like mentioned, primarily by optimizing trade. As little producing buildings as possible, and as many needing as possible, all internal trade of course.
Legacy view. Leading in Legacy after about 200 turns.. Just the times three modifier means that winning on Legacy would take a LOOOOOOONG time... Decadence ratio of 0.38 just by sheer empire size.... Producing Culture is pointless since with this empire size i'm bottom tier anyway...Chance to gain regression token is 10% thanks to Temple. So about every ten turns i should conquer an objective which is easy...
Finished Temple of Solomon.. Very Nice! Also repaired Tower of Bable, waiting on repairing the Hanging Gardens (hasn't come up yet).
Standard army. 8 Provincial Heavy Infantry (5/5 4/3) which don't have Clumsy. They are now my main troops for mountain terrain. 16 Heavy Cavalry (5/5 3/3) and 16 Provincial Horse Archers (Range Attack 9, so support 3). Each army is accompanied by a small 16 regular Infantry army for sieging. I personally found Phalanx and Judean Zealots mediocre units and only used them in the first 40 odd turns, and ditched them when i got my hvy Cav.
So the succes part is, Yes I think a WC is possible, it just takes till our sun goes supernova
and I feel I proved what I wanted to prove, even though the map isn't just one color Hope you all like it!
