The siege of Berwick lasted four months in 1333 and resulted in the Scottish-held town of Berwick-upon-Tweed being captured by an English army commanded by King Edward III. The year before, Edward Balliol had seized the Scottish Crown, surreptitiously supported by Edward III. He was shortly thereafter expelled from the kingdom by a popular uprising. Edward III used this as a casus belli and invaded Scotland. The immediate target was the strategically important border town of Berwick.