Hugh O’Neill and the Tudors

(Christine) At the dawn of the 17th century, only one region of Ireland was largely outside of English control: Ulster. To change this, the Gaelic Irish heir to Ulster--Hugh O'Neill--was raised under close watch of the English crown. So what went wrong? Why did Hugh O'Neill end up in full rebellion against Tudor Queen Elizabeth I? And what exactly was the Flight of the Earls?