John Craig

John Craig M.D. (died 1620) was a Scottish physician, known also as an astronomer. He was physician to James VI of Scotland, and accompanied him to England. He also corresponded with Tycho Brahe, and associated with John Napier.

He was born in Scotland, the son of an Edinburgh tailor and merchant Robert Craig and Katherine Bellenden. The lawyer and poet Thomas Craig was his older brother. He graduated M.D. at Basle. Settled back in Scotland, after a decade and a half on the continent of Europe, he became first physician to James VI, whom he accompanied to this country on James's accession to the throne of England as James I.

In 1604, he was admitted a member of the College of Physicians of London.

He was incorporated M.D. at Oxford 30 August 1605; was named an elect of the College of Physicians on 11 December the same year; was consiliarius in 1609 and 1617; and died before 10 April 1620, when Dr. John Argent was chosen an elect in his place.

Paul Wittich taught him astronomy in Frankfurt an der Oder in 1576. John Craig was the author of Capnuraniae seu Comet, in Aethera Sublimatio, a manuscript addressed to his friend Tycho Brahe. Some of their correspondence was printed by Rudolf August Nolten. Craig's work was prompted by the Great Comet of 1577. The contact with Brahe was set up by William Stewart of Houston, who visited Denmark in 1589.

According to Richard A. Jarrell:

Much of the transition … to the Copernican system … occurred during the last third of the sixteenth century. To a surprising extent, this transition was a product of German-speaking astronomers, and those foreigners educated by or in contact with them. Tycho, although a Dane, was as much a part of German astronomy as the Scots Duncan Liddel and John Craig, or the Czech Tadeáš Hájek (Hagecius).

In fact Craig was an academic in Germany for an extended period. He was in Königsberg in 1569, and in 1570 as a medical student under Caspar Peucer. He was in Frankfurt-on-Oder in 1573, teaching mathematics and logic. He returned to Scotland in 1584.

Craig may have been the person who gave John Napier of Merchiston the hint which led to his discovery of logarithms.Anthony à Wood states that

one Dr. Craig ... coming out of Denmark into his own country called upon John Neper, baron of Murcheston, near Edinburgh, and told him, among other discourses, of a new invention in Denmark (by Logomontanus, as 'tis said) to save the tedious multiplication and division in astronomical calculations. Neper being solicitous to know farther of him concerning this matter, he could give no other account of it than that it was by proportionable numbers.

This story may not be independently verifiable. Napier himself informed Tycho Brahe, via Craig, of his discovery, some twenty years before it was made public.