In prehistoric times, before the conversion of Ireland to Christianity by St. Patrick, the clan system prevailed there, as it did in other countries of Europe. A "clan," or "sept," consisted of a number of families and was ruled by a patriarch, the greatest warrior, or the oldest man. A "tribe" was a larger group, consisting of several clans or septs more or less related to each other and occupying a distinct and separate territory under the command of a chieftain. Several tribes composed a nation, as the word is used among the North American Indians, ruled by a "ri," or king, while the "ard-ri," or over-king, a supreme monarch with jurisdiction extending to the remotest shores of Ireland, reigned and resided at Tara until the sixth century, with the province of Meath as his own exclusive demesne for the use and support of his family and his court. He received tribute from the local kings or "ri" and was elected by their votes. Occasionally at his call, or at stated intervals, the kings and chiefs would assemble at Tara to consider matters of importance to all, to adopt laws and regulations for preserving peace and promoting the welfare of their subjects and protecting their common interests. Several feasts, held there annually, were attended by the minor kings, chieftains, and nobles who were followed by large retinues. Their warriors engaged in games, sports, and tournaments to encourage the physical development of the race and teach the arts of war. From the throne of the ard-ri decrees were announced, laws proclaimed, justice dispensed, and prizes awarded. According to the annals of those early days, one hundred and forty-two kings reigned at Tara during a period of two thousand five hundred and thirty years, when the place was abandoned in consequence of a curse pronounced by St. Ruadhan of Lorrha for the failure to punish Hugh Garry for the murder of a monk. Until the time of Cormac Mac Art, greatest and most luxurious of all the ancient kings of Ireland, the rulers who sat at Tara were pagans, but he was converted to Christianity, and the annalists in glowing lines describe his piety and his devotions. According to the ancient laws, the king of Ireland could not have a blemish upon his person, and Cormac was obliged to abdicate power and authority and retire to the top of the Hill of Skreen, across the valley from the Hill of Tara, because his left eye was put out by an arrow shot by Ængus, a rebellious chieftain, who is believed to have been under the influence of Druid priests, to punish Cormac for accepting Christianity.