Art plays a central role in our society as a representation of who we are and as a challenge to our values. This thesis looks at the moment in which art became an object of speculation and the art world had to face the challenges of commercialisation. Throughout the nineteenth century the French State was the main patron of the aitists. The Salon, the annual Academic exhibition, provided a secure career path and a reliable income from public commissions. Around 1880, State patronage began to decline prompting a whole generation of artists to seek representation by private dealers. Thus began a thirty-year struggle for a new market structure. This thesis considers the role played by the art dealers in this change, an area which, till now, has largely been neglected. The starting point was the business history of the Galerie Georges Petit questioning how this gallery grew into the largest in Paris and maintained its prime position for over thirty years. In 1879 Georges Petit, inhelited a smaller gallery from his father, which dealt mostly in plints. Eyeing the potential of the expanding art market Petit decided to increase the scope of the business. In May 1882 he inaugurated a new building to house the gallery and presented his first exhibition in this vast space, luxuriously decorated in velvety fabrics and with comf01table chairs for relaxed and sociable enjoyment of the works on display. Petit invented the exclusive gallery expelience, which became important as a means to promote the work of contemporary aitists to the financial elite. The initiatives of the Galerie Georges Petit influenced other gallelies significantly. A comparative study of the activities of the Galerie Arnold & T1ipp, also founded in 1882, revealed a surplising level of collaboration between dealers. Despite fierce rivalry art dealers shared investments and risks, passed on clients, and used each other's expertise to authenticate works of ait. The results of the research have shown that dealers accepted their patronage of the arts with an entrepreneulial approach introducing innovative exhibition concepts, assuming a new ment01ing role and establishing relationships between artists and collectors. This thesis has also provided new insight into the financial structure of the commercial galleries and the development of contractual agreements between artists and dealers. Art dealers promoted the transition from public to private patronage actively and must therefore be p:;v~ntral to the development of the modern art market.