There is another and perhaps more cogent reason. Diarmait left his son, Colmán the Little, king over Midhe proper, _i.e._ Westmeath and most of King's County and County Longford; and another son, Aedh Sláne, before mentioned, king over Bregia, _i.e._ County Meath and parts of Louth and Dublin counties. This is a further instance of that process, described in a former lecture, of creating mean lords. From these two kings sprang two distinct dynasties. Colmán's line, Clann Cholmáin, dominated the western territory; Aed Sláne's line, Síol Aeda Sláne, the eastern territory. The process of appropriation was continued in detail by their descendants. "Clann Cholmáin," says an ancient genealogist, "were distributed throughout Midhe so as to possess the lordship of every tuath and perpetual sovereignty over them." In like manner, an old genealogical poem relates the distribution of Aedh Sláne's descendants in lordship over various territories of Bregia. The annals show that, between these two families so closely related, a fierce and bloody feud broke out, with continual reprisals, lasting for many years. Tara was in the possession of Aed Sláne's line. After the year 734, the kings of this line were excluded from the high-kingship, but nevertheless continued to hold undisputed authority over all Bregia, including Tara, until the close of the tenth century, when their dynasty was suppressed by the high-king Mael Sechnaill, who was also the chief of Clann Cholmáin. These facts quite sufficiently explain why, after 734, no king of Ireland could occupy Tara without an army. The political affairs of southern Ireland during this period are remarkably tranquil and undiversified. In Munster, there was probably more abiding peace than in any equal extent of country in western Europe. The kings of Cashel appear to have steadily consolidated their authority and to have been content to do so without seeking to extend it beyond the bounds fixed in the fifth century. In the Book of Rights, the tributes payable to the king of Cashel far exceed those to which any of the other six principal kings in Ireland laid claim. There is an allegory related in the genealogies which indicates that at one time the supremacy of Cashel was challenged by the Eoghanacht kings of West Munster. This may have particular reference to one of these, Aedh Bennán, who died in 619, and who seems to have grouped under his own authority the western states in opposition to the king of Cashel. It is doubtful whether this ambition outlived him. His daughter, Mór Mhumhan ("Mór of Munster," as she is called), figures in ancient story. She became the wife of Fínghen, king of Cashel, and the ancestress of the most numerous family in Ireland, the O'Sullivans.