Kolbeinn Tumason (Old Norse: [ˈkolˌbɛinː ˈtumɑˌson]; Modern Icelandic: [ˈkʰɔlˌpeitn̥ ˈtʰʏːmaˌsɔːn]; 1173–1208) was a member of the Ásbirningar family clan, and was one of the most powerful chieftains in Iceland around the turn of the 13th century. Kolbeinn used his influenced the appointment of his allies into the clergy, such as Bishop Guðmundur Arason. However Guðmundur became a staunch defender of clerical independence, causing their relations to sour. In 1208, Kolbeinn and his followers attacked Guðmundur and his supporters in Hjaltadalur at the Battle of Víðines. Kolbeinn was killed in the battle due to head trauma.

Despite his opposition to Guðmundur, sources indicate that Kolbeinn was a devoutly religious man of some education. He is best known for composing the hymn Heyr himna smiður (English: "Hear, Smith of heavens") after receiving his dying wound. It is now a classic and often-sung Icelandic hymn.^[1]

• Árni Daníel Júlíusson, Jón Ólafur Ísberg, Helgi Skúli Kjartansson Íslenskur sögu atlas: 1. bindi: Frá öndverðu til 18. aldar Almenna bókafélagið, Reykjavík 1989
• Sigurður Nordal et al., Sýnisbók íslenzkra bókmennta til miðrar átjándu aldar, Reykjavík 1953.

• A live performance of this poem sung by Árstíðir