William Harvey (1578 - 1657) was an English physician and anatomist who also worked in Padua, Italy, and became a professor of medicine in London. He made one of the greatest discoveries in medicine — the circulation of blood — in 1628. Prior to his work it was thought that arteries contained air and blood was stored in the liver. He realized that the heart was a pump, and recognized the relationship between arteries and veins in the circulation. He was originally lampooned in the popular press for his ideas and castigated by his colleagues, but in 1672 his ideas were accepted by a decree of Louis XIV of France.