Here is my (very sloppy) shot at the scenario:

stro2601 Turn 51.ctr

There is much room for improvement as many unintended things happened that unnecessarily dragged the game out:

1.  Persian AI going crazy on the other continent and thus getting too many cities to easily vassalize him.
2.  Huns founding a city after losing theirs in the most annoying spot on some island far away, cost quite some turns to even get there...
3.  A war declaration I did presumably one turn to early, hence missing some war support. As a result I could not immediately vassalize Persia after winning, despite having all his cities (had 181 WS; needed 185 WS) and had to build up WS again and then redeclare and win again; costing minimum 4 turns.
4.  Terrain (hills/cliffs) and island/sea routes to the other players were pretty much nightmares. Trying again with total knowledge of the map would easily save some turns as you can plan your routes ahead and be more efficient that way.

It was a very fun scenario though. The battle mechanics are in my opinion some of the best parts of the game, so I really liked that the scenario focused on that. Some tips for other players and some general thoughts on this scenario:

1.  Getting war support up against everyone is essential. Therefore, consider
   1. Building the Forbidden City after going to Medieval.
   2. Spam Alliance Proposals just to have them rejected to get demands.
   3. Build a war support focused religion.
2.  Get another horse resource early to build some Markabata. They are great units for this scenario as they are very mobile and ranged units. Don't forget to bring some Praetorians as well, or otherwise you won't be able to capture cities.
3. Get the combat strength of your units up by using homeland ideology and Aristocracy and Professional Soldiers cvics.
4. Going up in the eras is pretty much essential as it lowers the cost of vassalization and especially the Medieval era offers very nice cultures for this run. I took the Norseman, so I could easily get to the other continent. Alternatively, this might also be possible by building the Great Lighthouse!? If so, one could consider the Aztec or the Mongols whose Legacy Traits also fit very nicely. Going to Era IV is not required I'd say, but Spanish are obviously great because of their Legacy Trait as well.