The history of the Macdonalds and Lords of the Isles by Alexander Mackenzie states that there were two families that descended from Reginald, King of Isla; that of his son Donald,and that of Ruari, also known as Roderick, which later descendants called themselves Macruari.
The Irish historians record them as being very warlike, and not prone to seek peace.Donald inherited the lordship of South Kintyre, Isla and some other islands. Roderick received North Kintyre, Bute and the lands of Garmoran, from Ardnamurchan to Glenelg, which had formerly been the possessions of his uncle, Angus MacSomerled. The Isles and other possessions of Somerled had been first divided amongst his three sons, then redistributed between the two surviving sons Dugall and Ranald and now had been divided a third time. The Isle of Bute was originally inherited by Somerled's son Angus, but he died and his sons left no male heirs, so the island was taken by Ranald and it thus passed to his son Ruarie, who was also called Roderick.
One of Angus' sons left a daughter named Jane, who married Alexander, the son of Walter the High Steward of Scotland. Alexander claimed Bute in her right and the dispute was eventually settled by Ruari being expelled from Bute, which was immediately seized by the Scots. Ruari's lineage ceased in the male line about three generations later, continued by a female named Amie, who married John of Isla, who was a great grandson of Donald of Isla. This in effect brought two lines of descent into one descent from the House of Somerled.
Alexander II inherited the throne of Scotland in 1214 and almost immediately, the MacWilliams and MacHeaths rose in a rebellion and they were helped by the grandsons of Somerled. Peace was regained by 1221, and Alexander then proceeded to attack Argyll intending to conquer it and bring the house of Somerled into subjection. Fate was not entirely on Alexander's side. A storm drove his fleet back and winter was soon approaching, so they abandoned their goal temporarily. The next year Alexander started out on a new expedition. It appears from the accounts of John of Fordun and Wyntoun, that he was successful in removing some of the descendants of Somerled from their lands, forcing them to take refuge in Galloway or with others who were kin to them. Many of them submitted and gave large sums of money and hostages to ensure their future allegiance. If there were indeed a conquest of Argyll in 1222, it does not seem to have affected Donald and his sons. Alexander had caused diplomatic problems with the king of Norway, who considered part. But, again in 1249, Alexander II took a large force to the islands again, hoping to use to his advantage the recent death of the king of Norway.
He sailed toward Kintyre expecting Donald of Isla to see him and be in awe of such a large fleet. But Alexander was mistaken and Donald did not give up. Alexander sought alliance with Ewin of Lorn, but was eventually thwarted from his goal by death. He died at the age of 52 without having conquered Donald and his land. Ewin of Lorn also took advantage of the death of the king of Norway and attacked the Isle of Man and declared himself its king. Haco the King of Norway received word of this invasion by Ewin or Lorn and asked for the aid of Donald of Isla and hsi brother Roderick. They promplty gave Haco their aid, and with the help of the men of Man, expelled Ewin, who took refuge in his own lands. This aid rendered by Donald and Roderick formed an alliance between the ruling family of Isla and the Norwegian king.
Since Alexander II's successor, his son Alexander III was a child at the time of his death and Ewin of Lorn had been defeated, Donald of Isla had no more enemies to defeat and lived the remainder of his rule in relative peace. Although this does not mean he was not a violent man. It is said that he killed his uncle Dugall over a territorial dispute and that he beheaded a messenger that was sent from Alexander II demanding his allegiance. He also had his cousin Callum Aluinn put to death and his uncle Gillies banished to Ireland.
Apparently in his later years, he was filled with guilt over some of his deeds and made a pilgrimage to Rome, accompanied by seven priests. He made his confession to the Pope and received forgiveness from the church. He also gifted the church with lands as his father before him had done.
There is a legend that the Clan Donald takes its motto Air muir's tir or per mare oer terras from an incident Donald was involved in. He was supposedly in a contest with a rival clan for possession of land on Skye. It was decided that whoever put his hand on the shore first would win the land.At the last moment Donald's galley was overtaken and he was about to lose. He was so competitive that he cut off his own hand and flung it to shore and won the triumph. According to History of the Macdonalds and Lords of the Isles, he died in 1289 at Shippinage and was buried at Icolumkill. But The clan Donald by Archibald MacDonald, states that this date is incorrect, because his son Angus was head of the family for many years before this.
Donald is the man whom all MacDonald's receive their name, possibly aided by the fact that fixed surnames began to be the custom in the Highlands at about this time. In other words, men prior to this time tended to be called by their father's name, which changed from generation to generation. But at this time, families began to take the name of the family leader at that time and to stick with it from there on out. Whereas a man named John who had a son named William, this son would previously have been called William Johnson and having a son of his own named Donald who would have called himself Donald Williamson; now the custom would be for William and his son Donald to bear the surname Johnson. The houses of the other branches of descent from Somerled would have been independent of each other and would have taken different surnames in order to avoid confusion.
Donald left two sons Angus Mor MacDonald and Alexander, who was said to be the ancestor of the MacAlisters of Loup, The Alexanders of Menstrie , Earls of Stirling. Angus being the eldest, succeeded his father. These sons were by his wife, who was a daughter of Walter, the High Steward of Scotland.
Skye By Derek Cooper
History of the Macdonalds and Lords of the Isles By Alexander Mackenzie