Nicholas Kratzer
Nicholas Kratzer was a famous mathematician and mathematical instrument maker who lived and worked in the 16th century when Henry VIII was on the throne. Like many of the best mathematicians in the 16th century Kratzer was from Germany. He was born in 1487 in Munich. He went to university in Germany as well, but when he was about 30 years old he moved to England. In England he went to Oxford University where he was employed by Cardinal Wolsey to teach maths. He also made sundials and other mathematical instruments when he was in Oxford. One sundial which he made for Cardinal Wolsey is now in the Museum of the History of Science in Oxford. Another one was made for use outside in Corpus Christi College.

Later on Kratzer became Henry VIII's astrologer. In the 16th century astrology was very similar to astronomy. Both were very mathematical subjects. Kratzer was a friend of Hans Holbein who was Henry VIII's painter. Holbein painted a famous portrait of his friend Kratzer surrounded by mathematical instruments. The original painting is now in the Louvre Museum in Paris. A copy is in the National Portrait Gallery in London. Kratzer had many friends back home and often received information about political events in Germany. Because of this some people think he was also a spy, who sent information back and forth from Germany to England.