Three kings followed in the usual alternate succession during the next seventeen years, half of that period being comprised in the reign of Indulf, the son of Constantine the Second. The grant of Cumberland was not renewed, either on account of the distracted state of England after the death of Edred, or possibly because of the somewhat doubtful manner in which the former king fulfilled his engagements, and the connection of his successor with the still formidable ruler of the Dublin Norsemen; but the loss of the English province was soon compensated by the capture of Edinburgh, the first known step in the progress of the gradual extension of the Scottish kingdom between the Forth and Tweed. A century previously the jurisdiction of the successor of St. Cuthbert still reached as far as Abercorn upon the Forth, but henceforth it was bounded by the Pentland hills until about fifty years later, when the historian of Durham has to record a more important loss, and to mourn over the contraction of the diocese within still narrower limits.[89] Twice was Indulf called upon to repel the inroads of the Northmen, who appear to have crossed the eastern seas, and endeavoured to effect a landing upon the coasts of Buchan and Banff. On both occasions he was successful, driving the invaders to their ships, the latest victory, however, costing him his life, for he fell in opposing the descent of the Norsemen at Invercullen.[90] Sufficient time had now elapsed since the accession of the Dalriad princes to the throne of Scotland to develope the principle of division inseparable from the Gaelic system of government, each branch of Kenneth’s family endeavouring, after the lapse of a few generations, to shut out the other from the throne, and to monopolize the right to the alternate succession as the exclusive prerogative of their own peculiar line. Accordingly the reign of Duff, the eldest son of Malcolm the First, and representative of the senior branch of the royal family, appears to have been passed in a continual struggle against the pretensions raised by the now rival line of Aodh in the person of Indulf’s son Colin, and though at first successful, defeating Colin at the battle of Duncrub, [Sidenote: A. D. 965.] in which the Mormaor of Atholl and the Abbot of Dunkeld, partizans apparently of the defeated prince, were numbered amongst the slain,[91] he was subsequently less fortunate, and was driven by his rival from the throne, losing his life on a later occasion at Forres, a place so disastrous to every member of his family, where his body is said to have been hidden under the bridge of Kinloss, [Sidenote: A. D. 967.] tradition adding that the sun refused to shine until the dishonoured remains of the murdered monarch received the burial of a king.[92]