He studied at Jena, and became sub-rector of a school at Regensburg. He also served as minister of a Lutheran church at Wickerstadt in Weimar. He later preached at the cathedral church in Naumburg, Saxony.
Dempster's dedication of his edition of Rosinus' Antiquitatum romanarum corpus absolutissimum to King James I won him an invitation to the English court.
- José Rabasa; Masayuki Sato; Edoardo Tortarolo; Daniel Woolf (29 March 2012). The Oxford History of Historical Writing: Volume 3: 1400-1800. Oxford University Press. pp. 254–5. ISBN 978-0-19-921917-9. Retrieved 14 December 2012.