Denmark's monarchy consolidated under Gorm the Old and Harald Bluetooth, whose Jelling Stones mark the nation's "birth certificate" and the official transition from Norse paganism to Christianity. Fleeing conflict in Scandinavia, Norse explorers settled Iceland starting in 874, an era of migration and land-taking recorded in the detailed genealogies and anecdotes of the Landnámabók. These settlers established the Althing in 930, a sophisticated proto-democratic parliament that utilized a decentralized system of chieftains and public courts to govern the Icelandic Commonwealth without a king.