The kingdom was in legislative and personal union with the Kingdom of Ireland from its inception, but the Parliament of Great Britain resisted early attempts to incorporate Ireland in the political union. Following the accession of George I to the throne of Great Britain in 1714, the kingdom was in a personal union with the Electorate of Hanover, from where the German House of Hanover originated. The early years of the newly-united kingdom were marked by Jacobite risings, particularly the Jacobite rising of 1715. The relative incapacity or ineptitude of the Hanoverian kings resulted in a growth in the powers of Parliament and a new role, that of "prime minister", emerged in the heyday of Robert Walpole. The "South Sea Bubble" was an economic crisis brought on by the failure of the South Sea Company, an early joint-stock company. The campaigns of Jacobitism ended in defeat for the Stuarts' cause at the Battle of Culloden in 1746.