The first biographies of Thomas Aquinas, the immensely influential philosopher and theologian, were written about forty years after his death. In the first (by William of Tocco) it is said that Aquinas was educated at Naples in grammar and logic by Master Martin and in natural philosophy by “Petrus de Ibernia” ie. Peter of Ireland. In the second (by Peter Calo), Aquinas is said to have quickly learnt all that Master Martin could teach him in grammar, leading to his transfer to Master Peter the Irishman who taught him logic and natural philosophy.
This would have been in the time period 1239-44. So who was this Irish teacher of Thomas Aquinas?
Research done in the eighteenth century (by a Dominican Bernardo Rossi de Rubeis) found two potential candidates in Naples at the right time. One, called Magistro Petro de Hybernia, has been excluded by later research, but the second, a Benedictine monk named Petrus de Donis and described as Ultonienis remains a possibility. This man might be the same as a Petrus de Dunis, a member of the Benedictine community of Down, founded about 1177-78 by John de Courcy who brought Anglo-Norman monks there from Chester.
However, we have no evidence that Peter of Ireland was present in the 1240s and he is not mentioned in early accounts of Aquinas. But there seems to be little reason for William of Tocco to invent a story that Martin and Peter taught Aquinas. It is neither colourful nor likely to inflate Aquinas’ standing, and it is information Tocco could have heard it from Aquinas himself.
At this distance it seems very unlikely we can ever know if Petrus de Donis was Peter of Ireland, but we can establish one thing based on the name alone. Peter of Ireland was probably Anglo-Norman, since Peter was not used as a name by the Gaelic population. It is also unlikely that an Irish man of Gaelic race at that time would have had a career that would take him abroad for his university education, most likely to Oxford (there was no Irish university), and from there to Paris and Naples. Peter of Ireland’s presence in the Sicilian court is interesting in its own right; it is plausible he had some connections with Normans in Sicily.