The English physician William Harvey (1578 – 1657) earns the accolade of being the first person to describe the circulatory system, largely laid out in his 1628 book On the Motion of the Heart and Blood. Harvey made his discoveries by largely ignoring the medical texts of his time, notable those of Galen, and instead by performing experiments and making dissections on animals. Sadly, animals were probably harmed in the making of his discoveries.
Like most prominent scientists of his time, Harvey was born into a wealthy family and attended university at Padua in Italy. Years later, he served as physician to King James I and Charles I, becoming a committed royalist in the process while building up a considerable medical practice.
Harvey lived in a period where most lives were still governed by superstition and witchcraft was still feared. Being a learned man with an extensive medical background he was skeptical of these claims, as most learned people are and should be. He and ended up examining several accused witches and played a key role in the acquittal all of the accused witches he examined.