Six descendants of four possible brothers born in the late 1700's had identical y-chromosome (12 markers) confirming C.P. Hamman's account of common ancestry. Two Hammans from the western Kosciusko family had identical and rare markers but were completely different from the Hammans of C.P.'s account. A number of Hamman families have now been established and further tests are continuing. Two descendants of a South African family of Hammans who have a family legend that one brother of their immigrant ancestor went to America, have been tested. They match each other but so far do not match any of the American Hammans who have been tested.