The Kalmar Union (Danish, Norwegian, and Swedish: Kalmarunionen) is a historiographical term meaning a series of personal unions (1397–1523) that united the three kingdoms of Denmark, Norway (with Iceland, Greenland, Faroe Islands, Shetland, and Orkney), and Sweden (including some of Finland) under a single monarch, though intermittently and with a population of less than 3,000,000.