Arumer Zwarte Hoop
The leader was the farmer Pier Gerlofs Donia, whose farm had been burned down and whose kinfolk had been killed by a marauding landsknecht regiment.After this he gathered angry peasants and some petty noblemen from Frisia and Gelderland and formed the Arumer Zwarte Hoop.[3] Under the leadership of Donia (nicknamed Greate Pier for his size), they employed guerrilla tactics and achieved several victories such as the successful siege of two Hollandic castles and the city of Medemblik.Jelckama also achieved some minor victories, but proved to be a less competent commander and slowly lost men.Jelckama and his soldiers indulged in acts of piracy and sacked many villages in the Frisian lands, losing the trust and support of their own people.