The following was translated from text found at the family site:
How did the family name Korzelius and de Looff come to The Netherlands?
As far we know, the name de Looff was registered for the first time on 29 th March 1713 in Kortgene. This was Thomas de Looff from Machelen on the Leie in Belgium and he married Cornelia Pampus. From this marriage was born, on 1st October 1713 the first Dutch de Looff, named Johannes. People in The Netherlands born with the name de Looff, are relatives of Thomas de Looff born 9th July 1674 in Machelen.
The family name Korzelius does not go back this far, as far as we know the first Dutch born Korzelius was born on the 15 th June 1843, on a ship, which was docked on the Rapenburg in Leiden. This first Dutch born Korzelius was Johan Peter Korzelius son of Johann Peter Korzilius II and Margaretha Katharina Letschert, both from the County Hessen-Nassau in Germany. The names Korzelius, Korzilius, Corzelius, Corselius, Corzilius, Corcilius and Corsilius belong to the same family. Within the same family around the eighteenth century and the beginning of the nineteenth century the name was written in a different way. In the family research it is shown that brothers and sisters actually sign their name differently.