Petrus Jacobi Thaborita (Latinised name form of Peter Jacobusz van Bolsward) (Bolsward, 1450–1527) was a Frisian monk, historian and writer. He is best known for his writings on the Frisian freedom fighter Pier Gerlofs Donia, and for writing down Donia's last words. In the extended works by Thaborita van Bolsward is found information on the Frisian chieftains warlords Jancko Douwama and Haring Harinxma (the Donia ancestor). About the death of Greate Pier, Pier Gerlofs Donia: Anton Reinhard Falck was the owner of the original documents, he lent these to the researchers Visser and Amersfoordt.