Mr. Peters and Mathilde Jakobs were related in two ways. They were third cousins once removed--Matthias Karst and Maria Katharine Kreuser were his great great grandparents and her great great great grandparents. They were also fourth cousins once removed--Peter Michels and Agnes Lanser were his great great great grandparents and her great great great great grandparents.

Source: K-J Tonner’s Kelberg data file. The first name of this person was not in the data file because he was living when the file was created. His last name was obtained from his parents’ family name.
… Peters and Mathilde were related in two ways:
third cousins once removed—Matthias Karst and Marka Katharine Kreuser were his gg grandparents and her ggg grandparents; and
fourth cousins once removed—Peter Michels and Agnes Lanser were his ggg grandparents and her gggg grandparents.