 He was expected to continue the family business while his younger brother, Melchior, was expected to become a scientist.In 1799, at the age of 16, Boisserée attended school in Hamburg, where he discovered his interest in art.After he returned to Cologne, Boisserée, his friend Johann Baptist Bertram and his brother Melchior began to systematically collect and save medieval paintings from the secularization processes at that time, initially with a focus on paintings of German and Dutch origins.