The Frostating seal () shows king Magnus Lagabøte seated on his throne and giving the lawman the new Frostating law () at the Frostating. The seal commemorates Magnus's great effort to modernise the law-code. The representatives to the Thing—three deep—stand on the king's left side. The king sits in the middle on his throne with a crown on his head and a scepter in his hand, and with the Norwegian lion under his foot. Below in the seal are two bowmen; one aiming at a squirrel while the other aims at a bird. Both the squirrel and the bird sit in trees. The original of the Frostating seal is in the Diplomatarium Norvegicum, a source collection of Norwegian letters and documents from earliest recorded history until 1570. The seal is found on a document dated 1 June 1453, in Dipl. Norv. VIII no. 349 . A variation of this seal has lived on the coat of arms of Frosta.
