He was born in Neuhausen (now a part of Worms), and was educated in Heidelberg. The Protestant Cellarius may have left Heidelberg at the onset of the Thirty Years' War in 1618 or in 1622 when the city came in Catholic hands. His activities are unclear at this time but based on his later works it is conjectured he spent time in Poland and may have even worked as a military engineer there. In 1625 he married Catharina Elt(e)mans in Amsterdam, where he worked as school master of a Latin School. After a brief stay in The Hague, the family moved to Hoorn. From 1637 until his death he was rector of the Latin School in Hoorn, where Pieter Anthoniszoon Overtwater was conrector.