Check out how many active servers there is in this old battlefield game. Both vanilla and free Emulator Nexus or Venice Unleashed project rome servers.
To play for free online:
1. Create an account here
veniceunleashed.net/signup
2. Download Project Rome Client, unzip it, and copy the .dll file to the game folder:
veniceunleashed.net/downloads
3. Open the game and log in with the account created in step 1.