Frederick William and Brandenburg-Prussia gained a well deserved reputation in Europe and Frederick William became a very much sought after ally. By 1688, Brandenburg-Prussia’s military reputation was such that Frederick William and then Frederick I could pick and be selective with regards to her allies. The irony is that after 1660, her military was never really tested – yet its reputation remained very sound.
Frederick William adopted a policy of intrigue between France and Austria. Frederick William had no love for Louis XIV and the alliance between Brandenburg-Prussia and France during the Thirty Years War had been one of pure convenience. Frederick William felt no shame in denouncing an alliance when it suited his purposes to do so. Even when he gained a reputation for doing this, other states still wanted him as an ally.
However, in 1679, Frederick William reverted to Louis XIV again after unsuccessfully trying to get Pomerania from Sweden. This failure made Frederick William feel isolated and an attachment to France eased this concern – even if it was only to be temporary. Frederick William’s army absorbed vast sums of money and any foreign subsidies were more than welcome. Why did Louis XIV ally with a man who would almost certainly go back on the ‘deal’? Almost certainly because Frederick William had great status in Europe and especially in Eastern Europe. There was also the chance that Frederick William might become a long-term ally as well. For Louis XIV, it was a gamble worth taking.
How important was religion in determining Frederick William’s foreign policy? This is difficult to assess. He certainly considered catholic nations to be a threat to Brandenburg-Prussia but he also encouraged Roman Catholics to go and settle in Brandenburg-Prussia. He was also happy to ally himself to catholic France when it suited his purposes to do so. However, when it suited Frederick William, he did ally himself to Lutheran Sweden to act as a deterrent against the spread of Catholicism in eastern Europe.
The only constant theme in Frederick William’s foreign policy was that Brandenburg-Prussia came above all else.
The two most logical allies in Eastern Europe were Brandenburg-Prussia and Sweden. Both were protestant and both had fought against Roman Catholic nations. However, both nations were suspicious of the other so a major alliance between the two was never formed. In fact, from 1658 to 1660 and 1675 to 1679, both nations were at war with the other. As usual, the bone of contention between Sweden and Brandenburg-Prussia was Pomerania.