Civilization V: The Swedish Saga, part 3 (1702 A.D. to 1868 A.D.)
The time for war is nigh
1802 A.D.: Celtic spies uncover an impending Greek invasion of Graz. The Swedes prepare to defend.
Greece would have to go through Salzburg (held by the Celts) or Vienna (held by the Austrians) to get to me. As they're unlikely to get an open borders agreement with either, this means they'd have to declare war. This is assuming they don't try to attack from the West by sea, but from what I can tell, they don't have much of a navy on this side of the continent.
1804 A.D.: Greeks ask for an open borders pact with Sweden. The Swedes send them a painted ship's sail, which breaks the world record for the largest-ever depiction of the word "NOPE." Meanwhile, Sweden makes a declaration of friendship with tiny, impoverished France.
1806 A.D.: The Celts ask for aid in a war against the Danes. The Swedes accept, eager for a reason to relieve the tension of Danish forces in the border marches.