I'm uncertain as to the meaning of the word sponser, but one branch of my family is Niebuhr and I have considerable information on them back to a Christof Niebuhr, b. ca. 1687 in Prussia. There are Annas in each generation. These Niebuhrs later migrated to the Chortitza Colony in South Russia and a few of them emigrated to Canada in the late 1800's. If I can help, please let me know.