Einar Tambaskælver was a formidable bowman. He is mentioned in the Faroese kvæði Ormurin Langi, about the longship Ormen Lange which belongs to the Norwegian King Olaf Tryggvason and who asks Tambaskælver to become his "Ørvagarpur" (bowman).
The name Tambaskelvi/Tambaskælver is referring to Einars bow named Tambar, which trembles when he uses it.
Einar Tambaskælver dies together with King Olaf when, after a battle is lost, they throw themselves off Ormen Lange into the sea so to not be captured by their opponents, possibly in the hope of fighting another day.
References
Einar Tambaskælver Wikipedia(Text) CC BY-SA