This blog has mentioned Fermanagh's troubles in 1640-42. Now you can read or even download much of the history of Enniskillen by doing a Google search for "The History of Enniskillen and Manors in County Fermanagh" by W. Copeland Trimble.
This tells in dreadful detail the story of the Maguire and O'Neill uprisings that resulted the slaughter of many and the executions of some. That is only a few pages of the book, thank goodness. On the grounds that I have no more right to be ashamed of my ancestors' than they have to be ashamed of me (we each have ample cause for shame) and for the same reason I cannot apologize for them for that would be shear presumption on my part. 1640 was the time of the overthrow of Charles I of England and by 1635 most of the Great Plantation of Ireland by Protestant English and Scots had been completed except in Fermanagh.
The native Irish had their lands taken from them by force so that the English could also deprive them of their Roman Catholic faith and their Gaelic language and surnames. You may recall a book by Robert Ruark called "Something of Value". It tells in detail what happens when you take away a people's religion and social structure if it is not replaced with Something of Value.
The English came not to convert the Irish to a better faith or to improve their lot but to eliminate them as a political threat. The horrors of religious warfare was a great calamity for both the Irish and Scots Irish. It is easy after reading this to understand why both were such formidable Indian fighters in America. They had honed their skills on each other in Ulster.