The Dutch and English "fought" a 335-year war without any battles.

The Isles of Scilly, a quiet archipelago off the coast of Cornwall in southwest England, is the unlikely site of one of the longest wars in history — although the 335-year conflict between the Dutch and the English was because of a clerical error rather than lingering animosity. There were no battles or bloodshed, and everybody involved forgot they were at war after just a few months.
Starting in the 1640s, the British Isles were mired in a civil war between the Royalists, who supported the monarchy of Charles I and II, and Parliamentarians, who supported Parliament. The Dutch were longtime allies of the Royalists, but they predicted — rightly — that the Parliamentarians would be the victors. Wanting to be in England’s good graces after the likely change in leadership, they threw their support behind the Parliamentarians. The Royalists were, predictably, unhappy about this, and started raiding along Dutch shipping routes in the English Channel.