 Fragments from the ' doodtboeck ' (deathbook) of Ernestus van Harinxma.In 1613 Ernestus van Harinxma van Donia, a descendant of Haring Harinxma (Haring Donia) wrote a book concerning the deaths of Frisian nobles.In the 'Doodtboeck' he describes the violent struggle between the Schieringers and Vetkopers.