The union of Sega and The Creative Assembly has yielded its first fruit today, as the Rome: Total War Barbarian Invasion expansion pack is now headed to retailers across Europe and North America.

Set 200 years after the main campaign of Rome: Total War, Barbarian Invasion sees the outsider hordes massing on the borders of a declining Roman Empire. It's up to players to decide whether they will save Rome from its enemies or simply sack it. In addition to the new campaign mode, Barbarian Invasion adds new features and units to the real-time strategy game. There are 10 new factions, more than 100 new units, night battles, revamped artificial intelligence in battles, and more.

Rome: Total War Barbarian Invasion is rated T for Teen and retails for $29.95. For more on the expansion pack, check out GameSpot's hands-on impressions of the single-player campaign, or get the demo from GameSpot DLX.