John Craig (physician) facts for kids

John Craig (who died in 1620) was a Scottish doctor and a scientist who studied stars and planets (an astronomer). He was the personal doctor to King James. He also exchanged letters with famous scientists like Tycho Brahe and was friends with John Napier.

A Royal Doctor

John Craig was born in Scotland. His father, Robert Craig, was a tailor and merchant in Edinburgh. John's older brother, Thomas Craig, became a well-known lawyer and poet.

John Craig studied medicine and earned his M.D. degree from the University of Basel. He spent about 15 years in Europe before returning to Scotland. It is thought that he might have worked as a doctor for the king even before moving to England.

In 1588, Craig helped care for Agnes Keith, Countess of Moray, during her final illness in Edinburgh. He worked alongside a surgeon named Gilbert Primrose and an apothecary (someone who prepared medicines) named Thomas Diksoun.

When King James became King of England, John Craig went with him to London. On June 20, 1603, King James made Craig his first physician. This important role came with a yearly salary of £100. Another doctor, Martin Schöner, also became a first physician with the same salary a few weeks later.

In 1604, Craig became a member of the Royal College of Physicians in London. This was a significant achievement for a doctor at that time. He continued his medical career, becoming an "elect" (a chosen member) of the College of Physicians in 1605. He also served as a "consiliarius" (an advisor) in 1609 and 1617. John Craig passed away before April 10, 1620.

Studying Stars and Numbers

John Craig was also very interested in astronomy and mathematics. In 1576, he learned about astronomy from Paul Wittich at the University of Frankfurt (Oder). Craig wrote a special book called "Capnuraniae seu Comet, in Aethera Sublimatio." This book was about comets and was dedicated to his friend, the famous astronomer Tycho Brahe.

Some of their letters were later published by Rudolf August Nolten. Craig's interest in comets grew after he saw the Great Comet of 1577. His connection with Tycho Brahe was made possible by William Stewart of Houston, who visited Denmark in 1589.

Historian Richard A. Jarrell noted that many astronomers helped change how people thought about the universe. They moved from the old idea that the Earth was the center to the Copernican system, where the Sun is the center. Many of these changes happened because of German-speaking astronomers or those who studied with them. John Craig was one of these important people.

Craig spent a long time studying and teaching in Germany. He was in Königsberg in 1569 and 1570, studying medicine. By 1573, he was teaching mathematics and logic in Frankfurt-on-Oder. He eventually returned to Scotland in 1584.

John Craig might have given John Napier a key idea that led to Napier's invention of logarithms. Logarithms are a clever way to simplify difficult math problems like multiplication and division. A writer named Anthony à Wood mentioned that Dr. Craig visited Napier and told him about a new invention from Denmark. This invention helped save time in astronomical calculations by using "proportionable numbers."

Napier himself told Tycho Brahe about his discovery through Craig. This happened about 20 years before Napier's work was made public.