I started in a crappy spot, tried to expand. Relias plopped a town down right were I wanted to go, and claimed a farm and an earth shard. I dropped my own city closer to the resources than his, and constructed buildings into his zone of influence. This caused mine to push his back, and once I made contact with the shard, it became mine. I do not have the Shard Harvesting tech, but I got his shrine, and it is fully functional. The AI did not react in the slightest to this maneuver. I was unable to construct buildings into the actual buildable area of his town, but the influence zone was fair game.