Johan Isaksson Pontanus (1571 – 1639) was a Danish royal historiographer . Pontanus was the brother of the painter Pieter Isaacsz,was born in Denmarkbut grew up in Holland, but visited Denmark a couple of times and became acquainted with Tyge Brahe and Arild Huitfeldt . In 1604 he became professor at the school in Harderwijk and in 1618 he was appointed as the Royal Danish official historian, with the task of writing the history of Denmark in Latin. He was doing this work until his death, but only managed to publish the first part of his Historia Rerum Danicarum (1631).