The Duffs are descended from the original Gaels who inhabited the Highlands of Scotland long before the Roman invasion and the Christian era. Their ancient Gaelic name, Dhuibh, is pronounced Duff, and signifies a man of dark complexion and dark hair. The first Scottish Highlanders were members of ancient Germanic tribes characterized by a giant stature and great endurance. The people of Britain and the lowlands of Scotland were originally from France and southern Europe, but the Highlanders kept themselves apart and did not mingle with the despised lowlanders. The Duffs were of German Catti ancestry, having settled on the shores of Caithness. At first they hailed from the ancient Kournaovioi Tribe who occupied the north peninsula of Caithness; later moving down into Moray below the Moray Firth, where they were Mormaers of the Kanteai Tribe. At one time Moray included all of the north central Highlands, and the more reliable historians agree that the famous Thane of Fife came from Moray, prior to the great historical event which brought him to the attention of posterity. With the other Caledonian Tribes, the Duffs fought the Roman invaders and thus prevented the foreigners from gaining a foothold in Scotland.

According to an old genealogical manuscript, the Duffs were Mormaers of Moray during the era of the Pictish Kings, and were also prominent in Fife and Fothriff. Strath Avon, near the Cairngorm Mountains, was one of their old neighborhoods. The first Official Record of the Thanes of Fife was in the year 838. At that time Kenneth MacAlpine, who bore the blood of both Pictish and Scots-Irish Kings in his veins, had united two warring nations under one rule in the name of Scotland. When he appointed his Governors for the several Provinces, Fifus Duffus, or Duff of Fifeshire, was appointed Governor of Fifeshire.

In 1039 Queen Gruoch's (Shakespeare’s Lady MacBeth) second husband, Mormaer of Moray - who also belonged to the House of Duff, slew King Duncan and seized the throne and became King MacBeth. When Duff, the Thane of Fife, vowed that he would "not be ridden with a snaffle" and failed to aid in building MacBeth's castle, the pretender swore vengeance and drove Duff into exile. Duff fled to England to join forces with Malcolm, young son of King Duncan, and now that he had reached maturity, prevailed upon him to return to Scotland and take for himself the throne of his fathers.

Mormaer’s died in 1057, whereupon Queen Gruoch’s son by her first husband, Lulach, inherited the throne as king. Upon returning with an army, Duff found that King MacBeth had murdered Lady MacDuff and several of her children. Duff beseiged MacBeth's Castle of Dunsinane and drove him north into the Hills above the Dee River, whereupon Duff slew the Pretender on a slope above Lumfannaaine, and carried his head to Prince Malcolm.

When King Malcolm of Canmore was firmly established on the throne, he called a Parliament at Forfair in 1057, and rewarded those who had aided him in attaining the crown. King Malcolm honored with three sorts of privileges, which included that the Earl of Fife shall bear the heraldic red lion rampant of the Royal House, and shall set the Crown upon the King's head on the stone of Scone at his Coronation. He also decreed that the lineage of Duff should enjoy regal authority and power within all their lands, as to appoint officers and judges for the hearing and determination of all manner of controversies. King Malcolm also commanded Duff to build a great sanctuary in his own district of Fife where his people could seek safety in time of need. It was called the Gurth Cross, and it stood high in the Ochill Range, near the border between Fifeshire and Strathearne.

At that time the King raised the Thanes of his Kingdom to Earldoms, and Duff was made Senior Earl of Scotland and Commander in Chief of the Royal Army. Shaw MacDuff, second son of the Earl of Fife, was sent to investigate a Norse insurrection in the North, and finding the rebels strongly entrenched in a great camp at Elgin beyond the Spey River, the officer stationed himself at Braemar where he awaited the arrival of the king’s army. The Earl of Fife and his eldest son, Alexander MacDuff, accompanied King Malcolm to Monimuske to the king’s lands in Aberdeenshire, where they were joined by the younger MacDuff.

The old inhabitants, descendents of the ancient Picts who hated the Norse, joined the King's forces. Malcolm vowed to give Monimuske to the Church of Saint Andrew if he were victorious and proceeded west toward the enemy camp. The Moray men, unable to stand against the King's army, sought the assistance of the good offices of certain church men where the matter was arranged and the rebellion quelled. Shaw MacDuff was made governor of Moray and had his headquarters at Inverness, where Malcolm built a great new fortress. The ancient Castle of the Thanes of Fife stood half a mile west of Culross Abbey, not far from Saint Andrews. It was the fortress of Dunamarle, the site where MacBeth had slain Lady MacDuff and her children.

The Earl of Fife built another stronghold, MacDuff Castle, on a sea cliff above the waters of the Forth. It overlooked the coast line and the mountain vistas. Alexander, the oldest son of the great Mormaer, inherited the title and estates and continued to be prominent on the affairs of Scotland until the time of Alexander the First. Gillemichael, fourth Earl of Fife, witnessed the Charter of Holyrood granted by David the First, and Duncan the Sixth Earl was one of the nobles who treated for the ransom of King William in 1174.

Duncan MacDuff, the tenth Earlof Fife, also supported Alexander the Third at the Battle of Largs, where Haco and the Norsemen were defeated. In the latter part of the thirteenth century Duncan, Earl of Fife, married the niece of Edward the First, King of England. He was Governor of Perth, and perhaps it was natural that he took the side of his wife's people. At any rate, he opposed Robert the Bruce (of “Braveheart” fame), and Isabell, MacDuff's sister, was married to the Earl of Buchan, a Comyn - and mortal enemy to Bruce.

However, the Countess of Buchan was a lady of spirit, and a true Scotswoman, and she officiated at Robert the Bruce's coronation, placing the crown upon his head in accordance with hereditary right of her people. It was said that circumstance was responsible for the situation with the Earl of Fife, Isabell's brother, but when her husband, Earl of Buchan, learned that she had crowned Bruce, he wanted to kill her. Bruce had slain Buchan's kinsmen, the Red Comyn and his uncle, and when Isabell was later captured and displayed publicly in a cage by Edward the First, it was said that her vicious husband enjoyed her public humiliation, and tried to prevail upon Edward to kill her.

After Bruce won the War for Independence and the Scottish ladies were released, Buchan had been forced to flee England and Isabell returned to her own domicile in safety. However, Robert Bruce did not take kindly to the treatment accorded the ladies, and later, when the Earl of Fife and his lady fell into his hands, King Robert imprisoned them in Kildrummy Castle, Aberdeenshire, where they remained until the Earl's death in 1336. Although events did not occur quite as the Bard describes them, Shakespeare's MacDuff was an historic personage.