Civilization V: The Swedish Saga, part 4 (1868 A.D. to 1951 A.D.)
The Treaty dissolves
1887 A.D.: UNK forces face the first major military defeat in the nation's history, and are forced to fall back from Aarhus. All that remains are a few mountain regiments and the famed 1st Artillery.
1888 A.D.: The 1st Artillery's position is bombarded by the defending forces of Aarhus and almost wiped out. Nearly all of the UNK's Southern Corps falls back across the River of Storms to regroup.
Rome signs a research agreement with Denmark. This action causes the majority Unification Party Norse parliament to declare them no longer recognized by the Treaty of Vienna. Rome claims that the UNK has no right to make such declarations. With Celtica backing the UNK and Austria refusing to decide one way or another, this is largely identified as the dissolution point for the 35-year Treaty.
It's disconcerting how quickly things can change. Mere decades ago, I managed to unite the entire world against the mutual threats of Greece and Russia. Now, it seems, Rome, Denmark, and Austria have broken off to oppose myself, the Celts, England, and Spain... while our true, original enemies are left to do as they please. I fear it's going to take some kind of massive Southern invasion to get everyone to wake up and get back with the program.
1888 A.D.: UNK engineers finish paving a road from Sigtuna to Kaupang, greatly speeding the movement of troops to the Danish front.
The prime minister of the UNK publicly denounces Denmark, hoping to discourage Rome from aiding them in the future.