To be completely fair, Spulla diplomatically played about as well as Dantski, Nakor/DMOC, Plako, Inca, and the Byzantines. Yes, Dantski and Nakor/DMOC got in the CoW, but that was only because Kathlete approached them, not of any stellar diplo work of their own. All of those have no real long term allies outside of the CoW. I'd say the only true alliance in this game at this point is the threesome. It just so happens that of those that are not in a real alliance, Spulla was the one that got bitten (well, Byzantine and Plako did, but that wasn't really about diplo work as a
move and starting next to aggressive Rome, respectively).
