In 1521 Albrecht Dürer celebrated his 50th birthday during his trip through the Low Countries (now the Netherlands and Flemish Belgium). The diary he kept, shows no sign of birthday partying on that day. Instead, he mentions how much he spent on a few books, on the doctor and on gambling. The diary essentially is a business log book. It shows Dürer’s priorities: expanding his creative impulses, widening his network, and selling works. The diary offers a fascinating view on an artist, who can be considered as the first modern artist-entrepreneur.