of the Catholic nobility in attendance, they agreed to set up an alternative government known as the Irish Catholic Confederacy and drew up the Confederate Oath of Association. For the next ten years, the Confederates fought a three-sided war against Irish Protestant Royalists, Scottish Covenanters and English Parliamentarians. Causes The roots of the 1641 rebellion derived from the colonisation that followed the Tudor conquest of Ireland, and the alienation of the Catholic gentry from the newly-Protestant English state in the decades following. Historian Aidan Clarke writes that religion "was merely one aspect of a larger problem posed by the Gaelic Irish, and its importance was easily obscured; but religious difference was central to the relationship between the government and the colonists". During the decades between the end of the Elizabethan wars in 1603 and the outbreak of rebellion in 1641, the political position of the wealthier landed Irish Catholics was increasingly threatened by the English government of Ireland. As a result, both the Gaelic Irish, and the Old English communities increasingly defined themselves as Irish and were viewed as such by the newcomers. The pre-Elizabethan population of Ireland is usually divided into the native Irish and Old English, many of whom were descendants of medieval English and Anglo-Normans settlers. These groups were historically antagonistic, with English settled areas such as the Pale around Dublin, Wexford, and other walled towns being fortified against the rural Gaelic clans. By the 17th century, the cultural divide between these groups, especially at elite social levels, was narrowing; many of the Old English spoke Irish, patronised Irish poetry and music, and have been described as being "More Irish than the Irish themselves". Writing in 1614, one author claimed that previously the Old English "despised the mere Irish, accounting them a barbarous people, void of civility and religion and [each viewed] the other as a hereditary enemy" but cited intermarriage "in former ages rarely seen", education of the Gaelic Irish and "the late plantation of New English and Scottish [throughout] the Kingdom whom the natives repute a common enemy; but this last is the principal cause of their union". In addition, the native population became defined by their shared Catholicism, as opposed to the Protestantism of the new settlers. Plantations The Tudor conquest of the late 16th and early 17th century led to the Plantations of Ireland, whereby Irish-owned land was confiscated and colonised with British