Duke of Samsø was a title created for Canute Porse the Elder in the 14th century which was later recreated as the Landgraviate of Samsø in the 18th century.

Then the Island was part of the crown domain until the end of the 14th century when it was pledged to the Bishop of Aarhus. However it was redeemed to the Danish crown in 1407.^[1]

Later the Island was under royal control and was granted to Sophie Amalie Moth mistress of Christian V of Denmark. The title descended to their children. Under Danish law all sons of the titled nobility inherited the title but the estate was kept by the eldest male resulting in many offshoots.^[2]