The vice-rector at the Pontifical Irish College in Rome was pepper sprayed by masked intruders who had broken into the building.
Police in Rome are investigating the assault on Fr John Coughlan, a native of Riverstown parish, Co Sligo, in the Diocese of Elphin.
Fr Coughlan disturbed the men at the seminary, and was pepper sprayed by one of the intruders as they made their escape from the building.
"The three men were wearing masks and baseball caps. They were making their way up the main stairwell when Fr Coughlan became aware of their presence and challenged them verbally from the foot of the stairs," said a spokesman for the Irish seminary.
"They then turned to come back down and, as the first man passed by, he used pepper spray on Fr Coughlan's face in order to disable him."
The intruders then continued to make their escape from the building and out of the college's grounds.
Local police were alerted, and paramedics gave Fr Coughlan a medical check.
The incident occurred on November 30 and Fr Coughlan has since recovered.
He has suffered no lasting effects, the spokesman said.
While nothing was stolen, the entrance gate of the college received minor damage.
Founded in 1628, the Irish College is located in Via dei Santi Quattro in the heart of Rome, near the Baptistery of St John Lateran.
It is well known by many Irish couples who have opted to marry in its chapel.
In recent years, the seminary has been home to three communities: Irish seminarians, American seminarians and clerics undertaking international postgraduate studies.
In 2019, the college catered for 33 resident seminarians and 16 non-resident seminarians in formation as well as four Irish priests on the staff.
However, in June, the college's trustees, Archbishops Eamon Martin, Diarmuid Martin, Michael Neary and Kieran O'Reilly, announced that they would not be sending any Irish seminarians to the college for the academic year 2020-2021.
The number of Irish seminarians studying in Rome has sharply declined over the past decade.
In 2016, the college opened its doors to American seminarians, enabling them to undertake a semester abroad at the college - 16 non-Irish seminarians studied there last year.
Despite the assault on Fr Coughlan, the Irish College has announced that its annual advent service will take place online via YouTube today.