Haraeus first attended the Latin school of the Brethren of the Common Life in Utrecht and subsequently studied theology at the University of Louvain under Thomas Stapleton and Joannes Molanus.
[3][4] Back in the Dutch Republic he became a canon at St. John's Cathedral ('s-Hertogenbosch), later dean in Dunkirk and professor of theology at Tongerlo Abbey.
[7] Meanwhile, Haraeus had already started on his major history: Annales ducum seu principum Brabantiae totiusque Belgii tomi tres: quorum primo solius Brabantiae, secundo Belgii uniti principum res gestae, tertio Belgici tumultus usque ad inductas anno MDCIX pactas, enarrantur[8] (Antwerp 1623).
[4] Haraeus was one of several clergymen from the Netherlands who around the turn of the 17th century made important contributions to the young science of map-making (another was Petrus Plancius).
[17] As a final example, Haraeus Geographica restituta per globi trientes[18] (1618) shows the world in three globe-gores, with insets showing a map representing the 2nd-century worldview of Ptolemy at lower right, and a legend for the map in the lower center, explaining symbols which identify religious populations (a cross for Christian regions, a crescent for Islam, and a slanted arrow for barbarians).