The Plantation of Ulster (; Ulster-Scots: "Plantin o Ulstèr") was the organised colonisation ("plantation") of Ulstera province of Irelandby people from Great Britain during the reign of King James I. Most of the settlers (or "planters") came from southern Scotland and northern England; their culture differed from that of the native Irish. Small privately-funded plantations by wealthy landowners began in 1606, while the official plantation began in 1609. Most of the land colonised was forfeited from the native Gaelic chiefs, several of whom had fled Ireland for mainland Europe in 1607 following the Nine Years' War against English rule. The official plantation comprised an estimated half a million acres (2,000 km²) of arable land in counties Armagh, Cavan, Fermanagh, Tyrone, Tyrconnell and Londonderry. Land in counties Antrim, Down and Monaghan was privately colonised with the king's support.