Hieronymus Fabricius, also known as Girolamo Fabrizi or Fabricius ab Aquapendente, was an Italian physician and anatomist, the pupil of Gabriello Fallopius, whom he succeeded as professor of anatomy at Padua in 1562, and teacher of William Harvey. Fabricius made a detailed study of the valves in veins (although he misunderstood their function) and in his book Formed Fetus (1600) described his pioneering research in embryology.