Harbison, Sheelagh Helen (1914–2012), medieval historian, was born in Letterkenny, Co. Donegal, on 2 September 1912, the only daughter and youngest of three surviving children, to Frederick William MacSherry , bank manager, and his wife Helen (née MacDermott). After Sheelagh was born her parents had a fourth child, Stephen, who was severely disabled and died young. According to Sheelagh's son Peter, Stephen's needs were so great that he required all of his mother's attention and so the young Sheelagh was 'farmed out' to relatives (interview with Peter Harbison, May 2019). Among those she spent a great deal of time with was her mother's sister Gertrude, known as 'Auntie Gertie'. In 1922 Gertie married Dr John Macnamara and the couple brought Sheelagh to live with them in Corofin, Co. Clare. He owned an extensive library and became her unofficial teacher, instilling in her a love of learning and history.
At the age of twelve she was sent to the Convent of Notre Dame school in Birkdale, Lancashire, and during the summer holidays her paternal uncle Henry MacSherry introduced her to her cousins and brought her to play tennis in Eastbourne. Having completed her education, she took a secretarial course and briefly worked in an office before marrying Dr James Austin Harbison, then medical officer for Kildare and later for the city of Dublin, in 1934. The couple settled in Sutton and had two sons – John and Peter, who went on to become eminent in their respective fields as state pathologist and archaeologist. James Harbison was a distinguished medic, playing a critical role with Dr Noel Browne (qv) and others in the fight against tuberculosis.
In 1967 Gertie died, leaving Inchiquin House in Corofin to Harbison. Early the following year her husband James died, and it was at this point, Peter Harbison says, that his mother finally had 'the opportunity to carve out her own path, one that she took with relish' (Peter Harbison, 2019). At the age of fifty-six Harbison entered TCD as a mature student. As she had not studied Latin in school, she was only allowed to undertake a pass general studies degree initially. However, her ability and interest were apparent and in 1969 the university offered her the opportunity to transfer to a BA moderatorship degree in history and political science, on condition that she learn Latin and study under Professor Annette Otway-Ruthven (qv). During her time as an undergraduate student Harbison also became very friendly with Professor James Lydon (qv), and she wrote her BA dissertation on Geoffrey de Geneville (qv) under his supervision. She was awarded her degree in 1972, and then undertook an M.Litt. entitled 'William of Windsor (qv) in Ireland, 1369–76'. Having been awarded her master's degree in 1977, Harbison became a fixture in TCD life. Affectionately known to her students as 'Mrs H', she tutored in the medieval history department until the early 2000s, when she was delighted to be elected an honorary member of the Trinity Common Room. Colleagues remember her and Professor Anne Crookshank 'holding court' there after lunch most days.
As well as tutoring, Harbison contributed several important papers examining aspects of medieval Irish history. She wrote on Rindoon castle and Limerick castle for the Journal of the Galway Archaeological and Historical Society and Irish Sword respectively. She also wrote several papers on William of Windsor, including 'William of Windsor, the court party and the administration in Ireland' in England and Ireland in the later middle ages: essays in honour of Jocelyn Otway-Ruthven (1981); 'The absentee problem in Waterford and east Cork during William of Windsor's administration, 1369–76' in Decies: Journal of the Waterford Archaeological and Historical Society and 'William of Windsor and the wars of Thomond' in the Journal of the Royal Society of Antiquaries of Ireland. In honour of her friendship with James Lydon, Harbison also wrote an appreciation for him at the beginning of his Festschrift: Colony and frontier in medieval Ireland: essays presented to J. F. Lydon (1995).
Sheelagh Harbison died on 14 October 2012 in Beaumont Hospital, Dublin. Her funeral mass took place at St Fintan's church in Sutton and she was then cremated in Glasnevin crematorium. Remembered fondly in the family as 'Ma Hab', Harbison was described by her old friend and colleague Professor Jonathan Bailey as someone who had 'a wonderful sense of balance, humanity and fun' (Ir. Times, 27 October 2012).