In Retrospect: Neolithic activity at Knockadoon, Lough Gur, Co. Limerick, 50 years on

Sean P. O Riordain, MRIA, Professor of Celtic Archaeology at University College Dublin (UCD), died in 1957 at the age of 52. He was at the peak of his career, engaged in an ongoing research project at Tara where he had undertaken excavations at the Rath of the Synods (Raith na Seanad, Grogan et al. forthcoming), Raith na Rig (Roche 2002) and the Mound of the Hostages (Duma na nGiall) where a further season of work was carried out by his successor in UCD, Professor Ruaidhri de Valera (O' Sullivan 2005). O Riordain 's work at Tara turned out to be the final act of a very impressive engagement in archaeological research, much of it published in the Proceedings of the Royal Irish Academy. His papers published therein included those on his series of excavations on the Curragh, Co. Kildare (O Riordain 1950a); his consideration of Roman material in Ireland (O Riordain 1947a); and major excavations at Cush, Co. Limerick (O Riordain 1940), Garranes, Co. Cork (O Riordain 1942), Ballycatteen, Co. Cork (O Riordain and Hartnett 1943), and Letterkeen, Co. Mayo (O Riordain and MacDermott 1 952); that made a very significant contribution to our understanding of early Christian or early medieval Ireland. The co-authored volume on Newgrange and the Bend of the Boyne that appeared after his death (O Riordain and Daniel 1964) demonstrated that he was also very actively involved in the study of the passage tombs of the Bend of the Boyne. Sean P. O Riordain 's impact on Irish archaeology has been outlined in various papers (O'Kelly 1957; Cooney 1997a; de hoir 2002; Wallace 2004; Waddell 2005, 225-6) and as Waddell (2005, 225) has commented O Riordain 's work at Lough Gur occupies a central place in his achievement and career. From 1936 to 1954 (with a break in 1952-3) he worked in the Lough Gur area of south-east Co. Limerick, where as he put it, 'there is a small lake set in a group of limestone hills' (O Riordain 1954, 298). Fifty years on, his research programme in this area still ranks as arguably the most intensive excavation-based investigation of a landscape anywhere in Ireland (Grogan 2005a, 47), matched in scale only over the last decade or so by the archaeological survey and excavation associated with major infrastructural developments such as motorways. O Riordain 's work built on existing research (Windle 1912; O'Kelly 1942, 1943a, 1943b, 1944) and involved the