Bishop Robert moved here from Rosemarkie between 1214 and 1249 and built this cathedral. It was about that time that the finances of the diocese became sufficiently well established to support the staff of clergy necessary for the dignity of a cathedral foundation. The first building was not very ambitious, but additions made in the early 15th century were of a very high quality. These extensions may have been the work of a mason who also worked at Elgin cathedral.
The church when first built there was no structural distinction between the choir containing the high alter and the canons' stalls and the nave for the lay folk. to the north of the nave was a tower and off the choir was a range containing the chapter house (canons' meeting room), sacristy (where the priests prepared for services) and library. In the years around 1400 an aisle and chapel were added on the south side.
In the later Middle Ages many of those who could afford to do so added chantry chapels to their local churches. the intention was that they should be buried within these chapels and prayers chanted (hence the name) at the alter there for their souls. The south chapel at Fortrose, with its prominent tomb in the eastern arch, was of this sort, and tradition has it that it was built for Euphemia the countess of Ross (d.1400?), who was forced to wed 'The Wolf of Badenoch'. Two other tombs of note are that of Bishop Fraser (d.1545) and Bishop Cairncross (d.1545).
The reformation of 1560 did not result in the immediate abandonment of the cathedral, but by 1626 the buildings were in poor repair. At the end of the century there was little more than that can be seen now. The north range long remained in use as the burgh's tollbooth and the southern additions as a buriel enclosure.
Fortrose is also known as the home of the mysterious Brahan Seer, Known in his native Scottish Gaelic as Coinneach Odhar. His existence is legendary at best, and some have questioned whether he really existed at all. He is thought to have come from Uig on lands owned by the Seaforths, and to have been a Mackenzie, although both these details are in themselves questioned. He is better known, however, for his connections to Brahan Castle near Dingwall, and the Black Isle in Easter Ross.
He is thought to have used a stone with a hole in the middle to see his visions. The Brahan Seer worked for the third Earl of Seaforth, Kenneth MacKenzie. (d.1678).
As with Nostradamus, who wrote in Provençal, most of his prophecies are best known in translation, which can in itself be deceptive. However, there are no contemporary manuscripts or accounts of his predictions, so it is impossible to verify them.