Thorvald Nicolai Thiele was a brilliant researcher and worked as an actuary, astronomer, mathematician, and statistician.
Thiele was born in Copenhagen on Christmas Eve, 24 December 1838, and grew up in a prominent family and a culturally and intellectually stimulating environment. His father, Just Mathias Thiele (1795-1874), was private librarian to King Christian VIII of Denmark and director of the Royal College of Prints.
Thiele obtained his master's degree in astronomy from the University of Copenhagen in 1860 and his doctoral degree (Sc.D.) in 1866, based on a thesis about the orbits of double stars. In 1875 he became professor of astronomy and director of the Astronomical Observatory at the University of Copenhagen, positions he kept until his retirement in 1907. He was the founder and Mathematical Director of the Danish insurance company Hafnia from 1872 until his death in Copenhagen on 26 September 1910.
An important facet of Thiele's personality is his unique abilities as initiator. The Danish Mathematical Society was founded in 1873 on his initiative in cooperation with H.G. Zeuthen and J.P.C. Petersen. The Danish Actuarial Society was also founded in 1901 on his initiative.
The painting is the work of the well-known Danish painter P.S. Krøyer. T.N. Thiele is sitting at the fore-front. The painting is courtesy of the Royal Danish Academy of Sciences and Letters.
A short biography with emphasis on Thiele's scientific achievements can be found at "Thorvald Nicolai Thiele" in the Mac Tutor History of Mathematics.
An excellent account on Thiele's life and work is Steffen L. Lauritzen's book "Thiele: pioneer in statistics", Oxford, 2002.