Lydon, James Francis Michael (1928–2013), historian, was born on 12 May 1928 in Galway city, the second youngest of eleven children, to Daniel Lydon, a baker and owner of Lydon's bakery on Mary Street, Galway, and Catherine (née Hogan), who came from an Irish-speaking family just outside the city. The family house was in Forster Street, just off Eyre Square and, in an interview given the year before his death, Lydon described how much he loved growing up in Galway (O'Keeffe, Life and lore). Although their house was in the centre of a city, Galway was small, and close to both sea and countryside. As a child he swam every day and one of his fondest memories was of using the diving board on an army yacht moored in Galway Bay; he also spent a great deal of his time with his mother's family in the countryside, developing an affinity for Irish language and folklore, which he believed aided him enormously in his career as a historian.
Lydon was educated by the Patrician Brothers at St Joseph's College, Galway (better known as 'the Bish'), where his favourite subjects were science, Latin and English. Ironically, given his later career, he loathed history and almost failed it in his leaving certificate. He was also very engaged in sports at school: he loved hurling, but his real passion was rowing and, during the 1930s and 1940s when he was on the school team, the Bish developed a reputation as one of the top rowing schools in the country. In 1947 Lydon entered UCG with the intention of studying science but, according to his account, the queue for science was too long, so instead he joined the queue for mathematics. When it came to choosing subjects for his BA, Lydon discovered that Latin clashed with rowing-training and so he was forced to take history, along with logic, maths, English and Irish. It was the first in a series of fortuitous events that led to his lifelong engagement with the subject. He received a double-first in English and history in 1950 and hoped to go on and do a master's thesis on the imagery of early English poetry, a subject that he had loved during his undergraduate years. However, his proposed supervisor showed no interest in the topic and so he found himself once more in the history department, where Professor Mary Donovan-O'Sullivan (qv) encouraged the young scholar to undertake research into Ireland's contribution to the English wars of the thirteenth century.
Lydon spent the next two years in London, using the libraries and reading manuscripts in the Public Record Office during the day, and working as a railway porter at St Pancras station by night. The latter, he recalled, was a 'real eye-opener. My colleagues at the station were interested in two subjects – soccer and sex [and] of the latter they didn't believe in sparing us the gory details' (Ir. Times, 24 September 1998). He also attended meetings at the Institute of Historical Research (IHR) where he met the director, the famous Welsh historian, J. G. Edwards. They immediately hit it off and, when Lydon returned to Galway to complete his masters, he received a letter from the IHR inviting him to apply for a research fellowship, which he was awarded after a gruelling interview. Supervised by Edwards, Lydon completed his doctoral thesis entitled 'Ireland's participation in the military activities of English kings in the thirteenth and fourteenth centuries' in 1955. He was awarded a two-year travelling fellowship by the NUI in 1954. His mentor F. M. Powicke, the great English medieval historian, advised him to travel Europe, experiencing the culture and museums rather than archives and libraries. However, Lydon's continental trip was cut short at Christmas 1955 when his father died, and he then returned to London to complete the fellowship there.
On Powicke's recommendation, UCG created a junior lectureship post for Lydon in 1956, at a time when academic positions were scarce. He lectured in the history department, through English and Irish, until Professor Donovan-O'Sullivan encouraged him to apply for a junior lectureship in TCD, working with the formidable Professor Jocelyn Otway-Ruthven (qv). Having accepted the position in Trinity, albeit reluctantly initially, Lydon quickly rose up the academic ladder: becoming a full lecturer in 1962, a fellow of the university in 1965, an associate professor in 1967 and succeeding Otway-Ruthven as Lecky professor of history in October 1980.
Throughout the 1960s, as Lydon's career took off, Archbishop John McQuaid (qv) maintained the ban on catholics attending TCD without his written permission. As a catholic member of staff Lydon felt the ban was becoming increasingly untenable, and he and other catholic staff-members signed a petition seeking to have it overturned. In early 1967 he and a colleague David Thornley (qv) went further, visiting the archbishop in his palace in Drumcondra. They were met by McQuaid, fully robed, who sat upon a dais in front of the window – backlit and resplendent – and refused to countenance their request (O'Keeffe). Later that year both academics appeared on RTÉ's Late late show, arguing against the ban. Opposing them were Fr Patrick J. Brophy (future president of Carlow College) and Vincent Grogan (qv) of the Knights of Columbanus. According to Lydon, he and Thornley were so persuasive in their arguments that Fr Brophy switched sides and the audience gave them a standing ovation. In June 1970 the ban was eventually lifted, and Lydon felt that the Late late show debate was instrumental in making that happen (O'Keeffe).
Throughout his career, Lydon's contribution to the field of historical research was immense. In 1966 he published a paper, 'A survey of the memoranda rolls of the Irish Exchequer, 1294–1509' in Analecta Hibernica that brought to light a wealth of medieval documents previously overlooked in the Public Record Office in Ireland. His work in the PRO in London in the early 1950s was built upon by Dr Philomena Connolly for her two-volume calendar of Irish exchequer payments in the medieval period. Lydon wrote two books – The lordship of Ireland in the middle ages (1972) and Ireland in the later middle ages (1973) – which, together with his four contributions to volume two of the New history of Ireland (1987), brought the study of Irish medieval history to a wider audience. In addition, he also wrote The making of Ireland: from ancient times to the present (1995), a general history intended to replace Edmund Curtis's (qv) History of Ireland (1922). Showing an assured grasp of both modern and medieval Irish history, it stands as an accessible and authoritative survey. He also edited three ground-breaking essay collections: England and Ireland in the later middle ages (1981), The English in medieval Ireland (1984) and Law and disorder in thirteenth century Ireland: the Dublin parliament of 1297 (1997), and co-edited the multi-volume Gill history of Ireland (1972–3), a series of stand-alone books on different periods of Irish history which placed a far greater emphasis than previous texts on Gaelic Ireland. He contributed a large number of essays to both national and international journals which will be cited by historians for generations to come (Duffy, Analecta Hibernica, xxii).
In recognition of his contributions to the study of medieval history, Lydon was honoured throughout his career. He was elected a member of the Royal Irish Academy in 1967 and was president of the Royal Society of Antiquaries Ireland (1981–4). He was a member of the Irish Manuscripts Commission (1981–2006) and was part of the consultative committee for the Calendar of papal registers project (1986–2005). In 1988 he returned to his alma mater UCG to receive an honorary D.Litt. from the NUI.
Lydon never married, although he had two serious relationships early in his career and was once engaged. The relationships, however, did not work out because, Lydon says, both women realised that he was far too involved in his work: 'they had sense and married other people' (Ir. Times, 8 September 1996). On 25 June 2013 Lydon died in Willowbrook nursing home, Newbridge, Co. Kildare, and was buried in St Kevin's cemetery, Hollywood, Co. Wicklow, where he lived for more than forty years. His friend Brendan Kennelly summed up his life's work best in a poem included in a collection of essays honouring his career: