Andreas Cellarius (1596 - 1665) was a Dutch-German cartographer, mathematician, and astronomer. He was born in Neuhausen (now a part of Worms), and was educated in Heidelberg. Cellarius, being Protestant, may have left Heidelberg in 1618, at the onset of the Thirty Years' War, or slightly later, in 1622, when the city fell to Catholics. His activities are unclear at this time but based on his later works it is conjectured he spent time in Poland where he may have taken work as a military engineer. In 1625. he married Catharina Eltemans in Amsterdam, where he taught Latin. After a brief stay in The Hague, the family moved to Hoorn. From 1637 until his death he was rector of the Hoorn Latin School. Today Cellarius is best known for his Harmonia Macrocosmica of 1660, a major celestial atlas, published in Amsterdam by Johannes Janssonius.