Mide and Connacht and by him interfering (as would be the Uí Néill view) in the affairs of Armagh. Conchobar and Feidlimid met at Birr in 827 to discuss peace terms, and the very fact that "the king of Munster could force the high-king to a peace conference is indicative of Feidlimid's growing power". Conchobar was succeeded by Niall Caille in 833. With Niall, we for the first time see a reference in the annals of a Uí Néill leading an army against the Vikings; he defeated Viking raiders in Derry the same year. He sought to further expand Uí Néill influence in the south; in 835 he led an army to Leinster and installed Bran mac Fáeláin as king of Leinster, and also invaded Mide. This brought him into conflict with Feidlimid, however, and in 838 a conference (rígdál mór—"great royal meeting") between Niall and Feidlimid was held. This meeting did not result in any lasting peace though; in 840 Feidlimid led an army into Mide and encamped at Tara, thereby challenging the Uí Néill also in the north. In 841, however, Feidlimid was routed in battle by Niall in Leinster. His successors in the south would not be able to challenge the north again to this extent until some 150 years later. Intensified raiding and the first Viking settlements in Ireland The Viking raids on Ireland resumed in 821, and intensified during the following decades. The Vikings were beginning to establish fortified encampments, longports, along the Irish coast and overwintering in Ireland instead of retreating to Scandinavia or British bases. The first known longports were at Linn Dúachaill (Annagassan) and Duiblinn (on the River Liffey, at or near present Dublin). They were also moving further inland to attack, often using rivers such as the Shannon, and then retreating to their coastal bases. The raiding parties also increased in size, becoming regular armies—in 837 the annals report a fleet of sixty longships on the Liffey, carrying 1,500 men, and another one of a similar size sailing up the river Boyne, making their way into the inland territories and launching attacks on the lands of Brega in the south of County Meath. In general, from 837 onward larger Viking forces hit larger targets – such as the greater monastic towns of Armagh, Glendalough, Kildare, Slane, Clonard, Clonmacnoise, and Lismore – while smaller targets such as local churches with less material