Civilization V: The Swedish Saga, part 2 (430 A.D. to 1702 A.D.)

A Celtic cold war

835 A.D.: Large Celtic warbands are spotted on the border near Uppsala. The High King dispatches forces there to defend, knowing that the warring Stormland lords cannot hold the border while civil war continues between them.

For the duration of this entire game, the Celts have kind of been that creepy neighbor who you see coming and going, but who doesn't talk to anyone, and no one really knows what he does for a living. They were the first to found a religion, but they haven't made any attempts to spread it. They move their troops around near the Swedish and Danish borders, but they've never declared war. They kind of have a whole subcontinent to themselves up there, and no one really has any idea what goes on in it. Luckily, they don't seem to have any units that match my tech level, so any invasion would be quickly thwarted.

860 A.D.: The First German Crusade ends, dashed against the walls of mighty Vienna. Still standing as the largest and most glorious city on the continent, it becomes known as The Unbreakable City.

890 A.D.: With the threat of Celtic raiders still looming, a Swedish Great General takes up residence at Uppsala and builds the Storm Wall to keep the city safe.

Meanwhile, Sweden's economy struggles.

960 A.D.: Sweden's regional Lord-Governors implement a system of Civil Service, offsetting much of the economic downturn of the late 9th and early 10th Centuries.

This gives a nice boost to all of my farms that have access to fresh water, which includes all of the ones built along the Snowrun River in the Stockholm Valley.