615 AD
Our alliance expires and I don't feel like giving the Japanese anything to extend it. By AI standards they were decent allies, conquering a couple of cities - but only along their borders, not losing any, and in general, staying out of our way. They see that they've little to gain from continued conflict, as even their newly-built Samurai will not reach the front for decades, and sign peace with the beleaguered Scandinavians.
Oddly, until now, the Japanese had no contact with other nations besides us and the Vikings, unless you count the mythical Babylonians. But they apparently meet the Chinese and Mayans, and immediately sign a military alliance with the former against the latter.
King Brennus pays a personal visit to newly-conquered Stavenger, confounding pundits, who see little diplomatic value in a backwards tundra fishing village. He is greeted by the Jarl, who welcomes him with a locally brewed Lervig ale and some fresh mackerel.
Later he is awarded the "key to the city," which seems to be a fish on a stick, but nevertheless dutifully poses for a portrait to commemorate this momentous occasion.
Gandhi contacts us in a huff, Annoyed that the crew of the Barfinder is teaching the native population how to "twerk".
Brennus: That's a traditional Sumerian weather dance. They do it to "make it rain"... Actually, it technically
is education, just not with a capital E... Sigh, yes, they'll leave your coastal waters immediately.
620 AD
Conquer Stockholm, which may need to be moved slightly to provide Celtic fisherman access to the nearby whaling grounds.