Niall Noígíallach, or Niall of the Nine Hostages, was a high king of Ireland in the early fifth century. He earned his name because he was a warlord who was renowned for taking hostages. He was said to have taken one hostage from each Irish province – there were then five provinces in Ireland – and one each from the Scots, the Saxons, the British and the Franks.

The O’Neill clan, which was very powerful in Ireland for centuries, was descended from him. They provided several formidable dynasties in both Ireland and Scotland.