This collection of previously published essays reflects 25 years of research by Dáibhí O Cróinín into the subject of the medieval science of time and time-reckoning, or computus. Including much unpublished or ill-studied early Irish material, these essays brought material and interpretation to the fore of Irish medieval studies. The essays The oldest Irish names for the days of the Week? (pub. 1981); The computistical works of Columbanus (1997); Hiberno-Latin Calcenterus (1982); The `lost' Irish 84-year Easter table rediscovered (1987-88); An Ild-Irish Munich computus (1981). The irish provence of Bede's computus (1983).
Dáibhí Iarla Ó Cróinín is an Irish historian and noted authority on Hiberno-Latin texts, particularly eminent for his significant mid-1980s discovery in a manuscript in Padua of the "lost" Irish 84-year Easter table. Ó Cróinín was Professor of History at NUI Galway and Member of the Royal Irish Academy. He specialises in the history of Ireland, Britain and Europe during the Middle Ages and Hiberno-Latin texts.