A self-confident Soest from 1444 to 1449 freed itself from the Bishop of Cologne, who controlled Westphalia (the so-called "Soester Fehde"). Being no longer capital of Westphalia, the city aligned itself with the Duke of Cleves. This was a Pyrrhic victory, however; the city had shown itself strong enough to defy the powerful Archbishop of Cologne, but lost much of its trade: the "freed" town was two-thirds surrounded by territories with other rulers. When the last Duke of Cleves died in 1609 that dukedom was taken by Brandenburg and after a short siege Soest was added into it. During and after the Thirty Years' War, Soest lossed a lot of people and influence; at the lowest point in 1756 it had only 3,600 citizens.