Derry is very near the border with County Donegal in Ireland. The city has had a very close relationship with what is now County Donegal for centuries. The person traditionally seen as the 'founder' of the original Derry is St. Columba (also known as Colm Cille or St. Columb), a holy man and royal prince from Tír Chonaill, the old name for almost all of modern County Donegal (of which the west bank of the Foyle was a part before c. 1600). Derry and the nearby town of Letterkenny form the major economic core of northwest Ireland.