The Sea Kings of the West
The story of Clan Donald on the Isle of Mull begins with a saga of sea kings and warriors who once ruled the waves of western Scotland with an iron grip. To understand how they shaped Mull, we must start at the very beginning with their ancestor Somerled.
Long before the Lords of the Isles were known, Somerled was a leader of both Norse and Gaelic descent. He led a major uprising against Viking influence in the Hebrides, mastering naval warfare with small, fast birlinns that could outmaneuver the heavier Norse longships. By the time he died in 1164, he had driven back much of the Norse presence in the southern Hebrides and controlled several key islands, though these lands were separate rather than forming one continuous kingdom from the Isle of Man to Skye.

Dividing the Legacy
After Somerled’s death, his lands were divided among his sons. The Isle of Mull came under the influence of his son Dugal, who founded the MacDougall line. The MacDougalls fortified their control over Mull, using it as a local power base in the western isles.
Another branch of Somerled’s descendants became the MacDonalds, holding lands in Islay and Kintyre. These two branches would eventually become rivals, shaping the political landscape of the western isles for generations.
Robert the Bruce and the Gift of Mull
During Scotland’s wars of independence, the MacDougalls sided with the English and the Comyns, who opposed Robert the Bruce. Angus Og MacDonald supported Bruce, offering him shelter while he was a fugitive and later leading Highlanders at the Battle of Bannockburn in 1314. After Bruce’s victory, he rewarded Angus Og by granting the Isle of Mull to the MacDonalds, taking it from MacDougall control.
Angus Og’s son, John of Islay, became the first to call himself Lord of the Isles, ruling semi-independently with his own parliament and navy. Mull became strategically vital, sitting in the middle of the Sound of Mull, the main maritime route along the west coast, giving the MacDonalds control over regional trade and naval movements.

The Power of Aros Castle
Although the MacDonalds’ main seat remained at Finlaggan on Islay, they built Aros Castle near Salen on Mull to project local power. This rugged fortress allowed them to monitor the Sound of Mull and intercept ships that failed to pay tribute. From Aros, they oversaw local affairs, gathered vassals before campaigns, and managed nearby fertile lands, a rare resource in the Hebrides.
Because the MacDonalds controlled such a large territory, they granted portions of Mull to other families who pledged military service. This brought the MacLeans to the island, shaping Mull’s history for generations.
The Great Charters of 1390
Lachlan Lùbanach MacLean became a close ally of the MacDonalds in the late 1300s. Tradition says he and his brother secured land and a marriage alliance with the Lord of the Isles through bold action, though whether this involved a kidnapping or negotiation is uncertain. In 1390, the MacDonalds formally granted large portions of Mull to the MacLeans, including Duart Castle and the responsibility of guarding the eastern Sound of Mull, as well as the Treshnish Isles.
For about a century, the MacDonalds remained the senior power while the MacLeans managed the daily affairs of Mull. This arrangement allowed Gaelic culture and law to flourish under MacDonald protection, creating a golden age for the island.
The Secret Treaty and the Fall from Grace
The MacDonalds’ decline on Mull was caused not by battle, but by politics. In 1462, John MacDonald, the fourth Lord of the Isles, signed the Treaty of Ardtornish-Westminster with England, promising to support the English king in exchange for independence in northern Scotland. When the Scottish crown discovered the treaty, it used it as justification to dismantle the Lordship.
The crown stripped the MacDonalds of titles and legal rights, creating a power vacuum on Mull. The MacLeans, seeing the MacDonalds’ decline, aligned with the Scottish government, further isolating the MacDonalds.

The Battle of Bloody Bay
Tensions within the MacDonald family erupted in civil war when John appeared weak to his son Angus Og, who wanted to restore the clan’s honor through battle. Around 1480, their forces clashed in a naval engagement north of Tobermory, later called Bloody Bay. Fathers, sons, and cousins fought on galleys, causing devastating losses.
Although Angus Og won, the victory was hollow, decimating the clan’s strongest warriors. In 1493, the Scottish crown abolished the Lordship, ending the MacDonalds’ legal control of Mull and centuries of local rule.
Attempts to Return
After 1493, the MacDonalds tried to regain their ancestral lands through several uprisings. Donald Dubh, imprisoned as a child, escaped and led islanders loyal to the MacDonald name, launching raids from Mull’s hidden bays. Despite their efforts, the growing power of the crown and the MacLeans’ rising influence prevented success.
By 1545, the last major rebellion had failed, leaving Mull firmly in MacLean hands. The ruins of Aros Castle remain as a reminder of the MacDonalds’ former dominion. Their history on Mull tells a story of bold achievements, tragic declines, and a legacy of bravery and culture that still defines the spirit of the Hebrides.