The organization of the Roman Church was introduced about 1150 when Bishop Andrew was appointed to the northern see. The bishop and his immediate successors established themselves in the northern and wealthier section of the new diocese, where Halkirk was made the ecclesiastical centre. When Jarl Harold was forced to Blake submission to William the Lyon in 1202, the Scottish king strengthened the central power in the north by granting the south-eastern portion of the diocese to Hugh, son of Freskyn of Moray, a powerful magnate on the southern shores of the Moray Firth. From that time the Murrays steadily extended their power and Norse influence in that quarter gradually declined. Meanwhile the vast northern and western portions of what is now known as Sutherland were ruled by Celtic maormers. After the martyrdom of Bishop Adam in 1220 the power of the Murrays was increased by the appointment of archdeacon Gilbert of Moray to the vacant see. He transferred the bishop's seat from the Norse centre at Halkirk to Dornoch and erected his splendid new foundation as far as possible from the fierce Norsemen.
In the course of the thirteenth and fourteenth centuries feudal law and custom gradually replaced the earlier Celtic jurisdictions n0t only in the barony of Sutherland but also in Strathnaver and Assynt.
The Earl of Sutherland, Mackay of Farr, and MacLeod of Assynt were the chief barons of the country. Much of the history of Sutherland from the thirteenth to the end of the seventeenth century is made up of the rivalries and conflicts of these feudal lords. The royal power was of so little account that the whole north of Scotland beyond the Spey formed but a single sheriffdom. Not until 1503 was the King's Court established at Dornoch, though no doubt feudal law of a sort was administered by the bailies of the barons. In 1508 the Earl of Huntly became heritable sheriff of Inverness. The following year Adam Gordon of Aboyne married Elizabeth Sutherland, heiress of Earl John. The rise of the Gordons in Sutherland was marked by a further increase in the number of feudal conflict, then so prevalent.
One of the fiercest of these took place at Tutim in Strathoykell in 1408. Angus Mackay of Farr had married a sister of MacLeod of Lewis. After Angus's death his widow appears to have been maltreated by his son Hugh, and MacLeod of Lewis invaded Strathnaver with a large following of clansmen to protect his sister. The MacLeods of Lewis, having ravaged the country of the Mackays, were pursued and overtaken at Tutim. A fierce battle ensued, according to Sir Robert Gordon, only one of the Macleods, grievously wounded, was able to return to Lewis to relate that Malcolm MacLeod, chief of the clan, and all the rest of his men had been slain at Tutim.
Another fierce conflict occurred in 1427 at Drumnacoub, near Tongue. Thomas Mackay of Creich, son of Neil Mackay, who had fought so valiantly at Tutim, killed Mowat of Freswick within the sanctuary of St Duffus at Tain. In consequence of this crime Thomas Mackay was outlawed. Angus Murray of Culbin, who succeeded in arresting the outlaw, was rewarded by grants of Mackay's forfeited lands in Strathnaver. Murray, who invaded Strathnaver to secure possession of these lands for behoof of his sons-in-law, Neil and Morgan Mackay, met his foes at Drumnacomb. The fight, says Sir Robert Gordon, was so bitter that few survived on either side. The leader of the Mackays (John Aberich) "seemed to have the victory because he escaped with his life", so that Murray's invasion proved abortive.
In 1570 a feud arose between the Murrays of Dornoch and the Sutherlands of Skelbo, whom the Murrays defeated in a skirmish at Torranroy, near Dornoch. To avenge this defeat the Sutherlands called to their aid the Sinclairs under the Master of Caithness, and the Mackays under Mackay of Strathnaver, Sinclairs, Mackays, and Sutherlands attacked the Murrays in Dornoch, burnt the cathedral and the bishop's palace, and ravaged the neighbouring country.
For many years at this period the Earls of Sutherland and Caithness were in fierce conflict about questions of jurisdiction.
In his march through Sutherland in 1651 to the fatal field of Carbisdale, Montrose received scant local support. After his defeat he wandered for days in the wilds of upper Strathoykell until compelled to surrender. When he was taken to Ardvreck Castle, MacLeod of Assynt was from home at the time, but his wife, a strong Covenanter, at once reported his capture to the authorities and Montrose was transferred to Skibo Castle, whence he was taken to Edinburgh. Though MacLeod had no personal responsibility for the surrender of Montrose, yet the royalists never forgave him. After the Restoration he was compelled, owing to persecution, to sell his estates. The members of his family took refuge in the Netherlands, where their descendants are still to be found. At the same period several of the Sutherland lairds, including Robert Gray of Creich, Gray of Skibo, and Murray of Pulrossie, were subjected to heavy fines because they had taken sides against the royalists.
In the eighteenth century Sutherland remained loyal. In the rebellions of '15 and '45 the Earl of Sutherland took up arms against the Stuarts. Though the heritable jurisdiction was lost in 1747, the power of the family was greatly increased by the marriage in 1705 of the Countess Elizabeth to Earl Gower, afterwards Marquis of Stafford and first Duke of Sutherland. In the forty years after 1785 the Sutherland family made large purchases of land and property in the county until, by the purchase of Lord Reay's estates in 1829, the family had acquired practically the whole county except Skibo, Rosehall and Achany.
In 1811 the Countess Elizabeth, then Marchioness of Stafford, introduced extensive schemes for the "improvement" of the agriculture of the county, the making of roads, the plantation of woods, the creation of sheep farms and the establishment of a number of fishing villages. These schemes were unfortunately marred by acts of harshness towards small agricultural tenants particularly in Strathnaver and Kildonan .
After 1840 the wilds of Sutherland began to attract the attention of sportsmen and tourists. The extension in 1870 of the Highland Railway system to the county increased its value for sporting purposes. Since that date a very large area has been converted into deer forest.
Meanwhile the Crofters Act (1886) by providing security of tenure to the smaller tenants led to a great improvement in their dwellings and in their methods of cultivation. The benefits of this statute were further extended in 1911.