On the north side of the cathedral may have originally sheltered a pagan sacred fire which was later christianised. Many scholars, indeed, note that in pagan times there was a goddess called Brigit with a festival on Imbolg, 1st February, now the feast day of Brigid. Such pagan overtones are enhanced by the statement of Giraldus Cambrensis (Gerald of Wales), who, writing in the twelfth century, said that males may not enter the fire house.
His full description runs: "At Kildare, in Leinster, which the glorious Brigid renders ennobled, many miracles are deserving of being recorded, amongst which the fire of Saint Brigid comes first. This they call inextinguishable, not that it could not be extinguished, but because the nuns feed it with fuel and so carefully that it has ever continued inextinct from the time of the virgin, and notwithstanding the great quantity of wood that has been consumed during so long a time, yet the ashes have never accumulated, when in the time of Brigid, twenty nuns served their Lord there, she making the twentieth. After her glorious transit nineteen always remained and the number was not increased, and when each had kept the fire in order in her own night, on the twentieth night the last nun put faggots on the fire, saying, "Brigid, keep your own fire, for the night has fallen to you", and the fire being left so is found still burning in the morning. The fire is surrounded by a circular fence of twigs within which a male enters not, and if one should chance to presume to enter, which was sometimes attempted by giddy persons, he escaped not, without enduring punishment. Also, it is permitted only for women to blow the fire, and for these, not with their own breath, but only with bellows or fans."
Over the centuries at least two bishops had attempted to have the fire extinguished because of its pagan overtones-but with notable lack of success. With the dissolution of the religious houses at the reformation, however, the purpose of the fire house was removed and Archbishop George Browne of Dublin ensured the extinction of the sacred flame. As late as the eighteenth century one remaining wall was still standing; today only the foundations remain. To the south east of the cathedral, there is also a disused burial chamber known locally as ‘Saint Brigid’s Kitchen.’