The tourbillon movement, one of the most elegant complications in the world of horology, has played a crucial role in Arnold & Son's history. An exceptional watchmaker, John Arnold was an active participant in one of the most extraordinary partnerships in the world of innovative horology. Indeed, both he and A.-L. Breguet worked closely, sharing both their knowledge and passion. Evidence of their partnership is A.-L. Breguet's first ever tourbillon mounted in John Arnold's No. 11 movement, a watch that can be found today in London's British Museum.