How did Harald I Fairhair help unite Norway?

Harald I Fairhair, the son of Halvdan the Black, was the first king to claim sovereignty over all of Norway. His efforts to unite the country were driven by military conquest and strategic alliances:1

• Military Campaigns: After suppressing a revolt in the Uplands, Harald focused on the western coastal districts. His efforts culminated in the Battle of Hafrsfjord, which took place between 872 and 900. Following this victory, he proclaimed himself king of the Norwegians.12
• Strategic Alliances: Harald formed a crucial pact with Haakon, the earl of Lade, and other regional chiefs to pacify the western coast.12
• Administration: While he maintained tight control over his home district in the southwest, he ruled other regions indirectly by appointing lesser chieftains. This development of provincial administration was a significant contribution to his governance.1
• Economic Control: He consolidated power by acquiring wealth through the control of coastal trade.1

Harald’s policies, including his taxation system, led many opposing chiefs to emigrate to the British Isles and Iceland.1