Here is an excerpt from a book on the subject scottish families...

"This branch [MacAlister] of the clan Donald traces its history back to the 13th century, and its origin back to Alexander, or Alasdair, son of Donald of Isla and great-grandson of the famous Somerled. The clan territory was principally in Kintyre, and in 1481 Charles MacAllestar is designated steward of Kintyre. Later the clan was numerically strong in Bute and Arran. The principal family was the MacAlisters of Loup whose chieftan in 1493 was Ian Dubh. This family continued to figure prominently in the history of Kintyre, and their name appears in the General Band of King James VII and fought under Viscount Dundee at Killiecrankie, and in the following year he was present at the Battle of the Boyne.

His son Hector died without issue and was succeeded by his brother Charles, who married Janet Somervill, heiress of Kennox, and assumed the name and arms of Somervill in addition to his own. An important branch of the clan was the MacAlesters of Tarbert who were constables of Tarbert Castle, a strong-hold on Loch Fyne built by King Robert the Bruce."

-Bain, Robert. The Clans and Tartans of Scotland.
 Harper Collins Publishers 1968, 1976. 929.209411 B162 cl