The Society of the Governor and Assistants, London, of the New Plantation in Ulster, within the Realm of Ireland, commonly called the Irish Society or The Honourable The Irish Society, is a consortium of livery companies of the City of London set up in 1613 to colonise County Londonderry during the Plantation of Ulster. It was incorporated by royal charter of James I and consists of "six and twenty honest and discreet citizens of London" nominated by the livery companies. In its first decades it rebuilt the city of Derry and town of Coleraine, and for centuries it owned property and fishing rights near both towns. Some of the society's profits were used to develop the economy and infrastructure of the area, while some was returned to the London investors, and some used for charitable work.
The society remains in existence as a "relatively small grant-giving charitable body". Its educational grants are funded by its remaining property, including the Walls of Derry, a tourist attraction and heritage site, and fisheries on the River Bann. It is based in London, with a "Representative" resident in County Londonderry. It remains closely linked with the City of London: its Governor is traditionally a former Lord Mayor of London, and members of the Court of Aldermen and Court of Common Council of the Corporation of London constitute members of the Court of The Honourable The Irish Society.
The Nine Years' War between Gaelic Irish chiefs and the Dublin Castle administration of the Kingdom of Ireland ended in Gaelic defeat 1603, and the Flight of the Earls in 1607 left northwest Ulster open to colonisation. In planning the plantation of Ulster, King James I set out to defend against a future attack from within or without. In his survey, he found that the town of Derry could become either a great asset as a control over the River Foyle and Lough Swilly, or it could become an inviting back door if the people of the area were against him. He pressured the guilds of the City of London to fund the resettlement of the area, including the building of a new walled city, and the result was the creation of the society. The Virginia Company of London had been created similarly in 1606 to colonise North America.