About the close of the 13th and beginning of the 14th century a great part of the city was destroyed by fires, one of which consumed many of the public records, which had been lodged in St. Mary's abbey.
An attempt to found an university, made in 1311 by Archbishop Leek, who procured a papal bull for this purpose, failed in consequence of the unsettled state of the country but was revived with more success in 1320 by Alexander de Bicknor, the next archbishop.
In 1312, the mountain septs of the O'Byrnes and O'Tooles made an incursion into Rathcool (Rathcoole) and Saggard (Saggart), when the chief force of the city had been despatched into Louth, or Orgial, to quell an insurrection of the Verdons, but on its return, the southern invaders were forced to retire into their fastnesses.
Three years after, when David O'Toole and some others of his sept made a similar attempt, by placing an ambush in Cullen's wood, the citizens issued out against them with their black banner displayed and did execution on them for several miles.
During the reign of Hen. IV. the citizens adhered firmly to him throughout the civil war excited by the Earl of Northumberland and Owain Glyndwr, and caused a diversion in his favour by fitting out a fleet with which they invaded Scotland, and, after several landings on the coast, proceeded in like manner along that of Wales, whence they carried away the shrine of St. Cubie and on their return placed it in the cathedral of Christ-Church.
- In consequence of these services, they obtained from the king a confirmation of all their former charters, and the present of a gilded sword to be borne before the mayor in public, in the same manner as before the lord mayor of London.