On my mother's side I've been able to trace the Koops line pretty far back, at least into the 1600s. Today happens to be the 234th birthday of my 6 Great Grandfather, who was born on 2 March 1778, in the town of Pieze, in Drenthe, Netherlands. Here is the reference to his birth off of Drenlias.nl.
Peize, doopboek (1771-1811; DTB 120), 8 maart 1778, pagina 12
Gedoopt: Koob, geboren op 02-03-1778, zoon van Barelt Koobs en Roelfien Jakobs.
One of the interesting things is that his name is Koob and not Koop, and the same with his father's second name. Without seeing the original document it's hard to know if this is a typo or if the name has evolved over time.