The Shannon Barrier
The Irish annals make 1001 look, at first glance, like a year of brief notices: an abbot displaced, a northern king dead, a raid checked in Mide, and a causeway thrown across the Shannon at Áth Luain, modern Athlone. Read against the preceding years, however, these clipped entries describe a crucial pause in a struggle for supremacy. Brian son of Cennétig, king of Munster and leader of the Dál Cais, had emerged from the 990s with extraordinary momentum. Máel Sechnaill mac Domnaill, king of Mide and the leading Uí Néill claimant to the kingship of Tara, was still the established overlord of Leth Cuinn, the northern half of Ireland in traditional political geography. In 1001 their rivalry narrowed onto the midlands and, above all, the Shannon.