Philip van Dijk was an important eighteenth-century painter-dealer. During this period lots of dealers in paintings started out as painters, a combination also found previously in the seventeenth century. Quite a few painters began dealing due to the falling demand for contemporary art in the eighteenth century, and some of them sought new outlets abroad where there were many well-off collectors interested in both contemporary Dutch painters and the masters of the seventeenth century. Van Dijk, too, built up a clientele both locally in The Hague and abroad. Bills and receipts from Johan Hendrik, Count of Wassenaer Obdam, show that Van Dijk was actively involved in putting together the count's collection for more than 20 years. He bought old master paintings at auction as well as privately, painted several works himself, and was also a restorer. He provided similar wide-ranging services to Wilhelm of Hesse-Kassel, and bought paintings on the Dutch market for him. As a result of his painting skills, Van Dijk must have had a good eye for quality, and he could tell the difference between an original and a copy. Wilhelm sent the young painter Freese to Van Dijk's studio in The Hague, not just as an apprentice but also to learn the finer points of art dealing. Van Dijk was most likely also involved in the purchasing of paintings by other German rulers, among them Augustus III of Saxony and Christian Ludwig of Mecklenburg-Schwerin.