A fire in the attic of Trinity College's Graduate Memorial Building is believed to have damaged records belonging to some of the college's oldest student societies.
The fire broke out in the building at about 3 p.m. and the college authorities had to take several valuable portraits to safety.
Nobody was injured and students in the building left after hearing the fire alarm.
Some old records, books and other materials belonging to the philosophical and historical societies were damaged, although most will be "salvagable", said a Trinity spokes woman.
The cause of the fire is not known at this stage. Timber and slates in the roof of the building were also damaged.
It took firefighters almost three hours to bring the fire under control.
When it broke out eight-foot flames shot out of the chimney.
The college chancellor, the UN Human Rights Commissisoner, Mrs Mary Robinson, had just started a ceremony across the courtyard to confer honorary degrees, when college guards spotted the blaze.
Mrs Robinson eventually led the long procession of degree recipients past the fire engines and bystanders. "It was quite a shock," she said. `But still, the graduation must go on."