At the beginning of the 20th century, changes in taste and expectations of the public led private museums in Europe and North America to embark on large-scale acquisition of archaeological objects from the Mediterranean and the Near East. John Marshall (1862-1928) was an antiquities expert hired by the Metropolitan Museum of New York as purchasing agent in Europe on behalf of its Department of Classical Art in between 1906 and 1928. His mission was to secure for the Metropolitan a comprehensive collection of antiquities of high aesthetic standards and historical significance. During his agency, John Marshall was an attentive observer of the antiquities trade. Photographs and annotations on more than a thousand ancient objects circulating on the art market at that time have survived in his personal archive, later bequeathed to the British School at Rome and the Ashmolean Library at Oxford. This unpublished and very valuable resource shines light on the secretive world of art dealing and provides information on the history of many masterpieces of ancient and post-ancient art now in the largest museums of Europe and North America. Using information gathered by John Marshall, this book delineates how the trade of art and archaeological objects has impacted the perception of the Classical past in the modern Western world.