At the beginning I decided that the map doesn't favour any kind of roman tactics, so I went with horsemen (I don't regret it). I couldn't have known that this is such a screwed up pangaea, but even on a normal map the horse travel speed and the easier access to the resource is worth more than anything the legion has to offer. I consider catapults a very weak unit, because of the tech path. If you got iron, that means, that you are very close to the longswordsman. Actually, you can get them with just a few turns later, if you bulb steel with your first GS, and you can also get medieval from metal casting. I'd rather go to war with pure longswords than half swords, half cats. And if you'd like to add the cats to the longswords you already have, then by the time you build them, you can probably start to upgrade them to trebs. Anyways Rome got unique cats, that are slightly better, but the problem is not damage, it's speed and availability. Thats for the UUs. I didn't utilize the roman construction speed bonus, because the capitol site didn't favour it. The starting settler location is a very nice, gold heavy site, but it doesn't have much production.
So, I researched sailing and calendar first to improve the capitol, then went staight to horseback riding. I built a scout, a second warrior (which turned out to be inefficient play), 3 workboats, and I was hoping to steal a worker (it would have been the first time ever I'd do that), but Budapest didn't have any, so I was forced to slowbuild one to improve happiness resources to sell them. I only met Germany at that point, and even though he didn't have lots of cash, I could make a nice gold/turn deal for a wine once I managed to get it improved. I didn't get mining till I finished horseback riding, so the forested silk stayed that way for long.
I didn't have much money, so I didn't get any maritimes, I spent all I had to get the second horses tile, and to rushbuy a horseman while building an other one during my first golden age. I attacked Germany with the 2 horses and 2 warriors, but I was forced to attack before my horses got there, because I've seen his first settler and I didn't want to deal with a second city at this point. I got his settler, but somehow managed to lose both warriors. Probably for the best... I wouldn't disband them myself, so I'd have just paid the maintenance for the rest of the game, had they survived. Anyways, Berlin was mine.
Just after that I met a Japanese scout, so I could trade for their 2 horses (now I had 6 total) and managed to get some money from him to rushbuy some of them. I explored the middle peninsula with my initial 2 horses while the rest (and a very slow great general) catched up, just to find noone there. But I met everyones scouts, so I could make some more deals. I allied Venice, and after I went to war with Japan and lost my traded horses (which I was using at that moment) I also allied with Singapore for the 4 extra horses (and maritime). From there I just steamrolled everyone with the 6 horseman and gg.
I kinda went for a wrong tech at the end. I spent 20+ turns on Compass, because I initially though that I would need trade routes eventually. I could have gotten to medieval earlier if I went with currency or civil service. Well, it's not like it delayed anything important... I guess I could have had knights right by the end if I built a library instead of a harbour and ran some scientists...
So, I didn't build any settlers, didn't build any wonders, didn't have any trade routes (except 1 harbour one by the end), only annexed 1 city, and only because I screwed up the horse management with the Japanese.
Good game! And horses need nerfing. Or something like that.