What key details about ernst magnus donhoff can be extracted from the following bio? Bio: ernst magnus donhoff -lrb- ; 1581 -- 1642 , in elblag , polish-lithuanian commonwealth -rrb- was a baltic german who served the polish-lithuanian commonwealth in livonia and the polish-occupied duchy of prussia . he was born a member of the denhoff family , a noble family of east prussian origin -lrb- the german family names is donhoff -rrb- . always referred to as magnus ernst by marion grafin donhoff , who wrote an extensive genealogy and history study of all the family branches , magnus ernst donhoff was the founder of the eastern prussian line of the donhoff family . he came from livonia and for services to george william , elector of brandenburg , he established his residence in waldau near konigsberg . he was the brother of gerhard donhoff and kaspar von donhoff . he was married to countess katharina zu dohna ; they had four children . three of their sons were born at waldau . donhoff was castellan of parnu -lrb- parnawa -rrb- from 1635 , voivode of parnawa from 1640 , starost of tartu -lrb- derpsk -rrb- , telsiai -lrb- telszew -rrb- and of waldau in the pregel valley in polish prussia . donhoff belonged to the commission which from 1625 worked for a peace agreement between sweden and poland . he was also instrumental in the negotiations at the peace of altmark and at sztumska wies . donhoff became count -lrb- reichsgraf -rrb- of the holy roman empire since 1633 . his son friedrich graf donhoff , born in waldau in 1639 , took up service for the brandenburg electoral court .
A:
- title is reichsgraf- caption is ernst magnus donhoff- spouse is katharina zu dohna- death date is 1642- more is no- birth date is 1581- image is ernest magnus denhoff.png- death place is elblag , poland- occupation is castellan starost of tartu -lrb- derpsk -rrb- starost of telsiai -lrb- of telszew -rrb- starost of waldau parnu -lrb- parnawa -rrb- voivode of parnawa