Book excerpt: As a result of the Napoleonic wars, vast numbers of Old Master paintings were released on to the market from public and private collections across continental Europe. The knock-on effect was the growth of the market for Old Masters from the 1790s up to the early 1930s, when the Great Depression put an end to its expansion. This book explores the global movement of Old Master paintings and investigates some of the changes in the art market that took place as a result of this new interest. Arguably, the most important phenomenon was the diminishing of the traditional figure of the art agent and the rise of more visible, increasingly professional, dealerships; firms such as Colnaghi and Agnew's in Britain, Goupil in France and Knoedler in the USA, came into existence. Old Masters Worldwide explores the ways in which the pioneering practices of such businesses contributed to shape a changing market.