Excerpts from Books and Wikipedia
"This period was marked by the Crown policies of, at first, surrender and regrant, and later, plantation, involving the arrival of thousands of English and Scottish Protestant settlers, and the displacement of both the Hiberno-Normans (or Old English as they were known by then) and the native Catholic landholders. Gaelic Ireland was finally defeated at the battle of Kinsale in 1601 which marked the collapse of the Gaelic system and the beginning of Ireland's history as part of the British Empire. During the 17th century, this division between a Protestant landholding minority and a dispossessed Catholic majority, divided not only by religion but also by cultural origin, was intensified and conflict between them was to became a recurrent theme in Irish history. Protestant domination of Ireland under a Protestant Ascendancy was reinforced after two periods of religious war, the Irish Confederate Wars in 1641-52 and the Williamite war in 1689-91. Political power thereafter rested almost exclusively in the hands of a minority Protestant Ascendancy, while Catholics and members of dissenting Protestant denominations suffered severe political and economic privations under the Penal Laws." [Wikipedia]