PSA: The PC Steam game Crusader Kings II is free today, so if you're into conquering a historically acurate-ish pre-renaissance Europe then get on board. It has online multiplayer so you can figure out what the hell is going on with friends.

http://store.steampowered.com/app/203770/Crusader_Kings_II/

Sebastian Tudor and I already play it, but the more the merrier. It's been around for a while so there are tonnes of fun mods, like one which lets you turn all of Europe communist through force.