Johann David Passavant (1787−1861) was an unusual person. First trained as a merchant in his parents' business in Frankfurt, from 1817 on he developed into a Nazarene painter and finally became a co-founder of a scientifically oriented art history. His work on Rafael von Urbino and his father Giovanni Santi, published in 1839, is considered one of the cornerstones of art research. The author had dedicated it to the "highly commendable administration" of the Städel, which had supported the research enterprise as well as the printing. He had been closely associated with the institute for a long time and had been advising it on art purchases since 1817. In 1840, Passavant took up the post of gallery inspector at the Städel art institute. The artist and art scientist also set up a small private collection himself, which he bequeathed to the Städel in his legacy dated 1861.