Clan Maclean is a Highland Scottish clan. They are one of the oldest clans in the Highlands and owned large tracts of land in Argyll as well as the Inner Hebrides. Many early MacLean’s became famous for their honor, strength and courage in battle. They were involved in many clan skirmishes with the MacKinnons, Camerons, MacDonalds and Campbells. They were fierce Jacobites fighting in all of the Jacobite risings.
There are several different origins for the surname Maclean, however the clan surname is an Anglicisation of the Scottish Gaelic MacGilleEathain. This was the patronymic form of the personal name meaning "servant of (Saint) John". They are descendents of Loarn mac Eirc, a 5th century king of Dál Riata. The family grew very powerful throughout the Hebrides and Highlands through allegiances with the Catholic Church in the 9th century, the MacDonalds in the 13th century, the MacKays and MacLeods in the 16th century.
Gillean of the Battleaxe: The founder of the clan was a Scots warlord descended from the royal Cenél Loairn named Gilleain na Tuaighe ("Gillean (pronounced Gillane not Gill-ee-un) of the Battleaxe", who lived circa (1174–1249). The stories of Gillean being descended from the FitzGerald dynasty is fictitious, as the FitzGeralds are of Cambro-Norman descent and the Macleans are of Gaelic descent, having been in Scotland since the Dalriadic migration from northeastern Ulster in the earlier centuries AD. Gillean's great-grandfather was Old Dugald of Scone, born ca. 1050 during the reign of King Macbeth of the House of Moray, the principal royal line of the Cenél Loairn. He was a Judex (judge) and Councillor to King David of Scots.
Gillean's son Malise (from the Gaelic Maoliosa "Servant of Jesus") was thought by some to have taken the name Gillemor in 1263 and wrote his name as "Gillemor Mcilyn ("son of Gillean"), County of Perth" on the third Ragman Rolls of 1296. This has been disproved in "Warriors and Priests" by Nicholas Maclean-Bristol. Malise is said to have led his followers against the Norsemen at the Battle of Largs in 1263 during the Scottish-Norwegian War where the Scottish were victorious. Gillean's great-great-grandson settled in Mull and by 1390, Donald, Lord of the Isles gave land to his two brothers-in-law, thus starting the two main branches of the clan: Maclean of Duart and Maclaine of Lochbuie (both on the island of Mull where the name is still frequently found).
Source: Wikipedia