From Wikipedia

According to tradition, Clach an Trushal was erected by the Morrisons to mark a victorious battle over the Macaulays.

The most notable of the Macaulays was Dòmhnall Cam (also known as Donald Cam) (c.1560–c.1640) who appears frequently in Lewis lore as the subject of many stories told today in Uig. The Gaelic byname cam commonly means "squint" or "blind in one eye"; and according to tradition Dòmhnall Cam lost his eye in a quarrel with Gobha Ban (the smith of Kneep) who put out his eye with a red-hot poker. There are several Lewis places named after him. One such place is a shieling in Lochs parish, possibly suggesting a site where his cattle grazed. Another is the stack at Mangersta, where he is said to have hid from authorities.[32] According to Matheson, tradition current in the 1970s stated that Dòmhnall Cam was the least formidable of his brothers, however what he lacked in physical strength he made up in grim determination.[33] He often appears in stories as being a fierce fighter with a short temper.

Tradition states Dòmhnall Cam fought in Ireland as a mercenary during the Irish wars, and that on an expedition to Derry he made a name for himself. It is said that he was challenged to a duel by "the Great McBane", a champion of an opposing army. Dòmhnall Cam's victory in the duel is said to have been commemorated in a song called Ceann na Drochaid, however no such song by that name now exists. According to Matheson, the song may actually be a pibroch. There are two known pibrochs with similar titles, Ceann na Drochaide Mòire, and Ceann na Drochaide Bige, however both of these relate to the Macdonalds and not the Macaulays. According to F. W. L. Thomas, the tradition of Dòmhnall Cam's exploits in Ireland was based upon the confusion of an Irish battle fought at a place called Beul na Drochaid, in 1495. One of the leaders in the battle was a Sligo chief named Dòmhnall Càm Mac Donnachadha. Even so, Matheson thought that it was possible that Dòmhnall Cam could have taken part in an expedition to Ireland because in 1545 the Macleods of Lewis were one of the Hebridean clans who entered into the service of Shane O'Neill, who was then in rebellion against Elizabeth I of England. This Lewis Macleod adventure was however an inglorious one, and they soon returned home to Scotland. Matheson also conceded that there is no connection between the Lewis Macleod's expedition and Derry where the Lewis tradition ties Dòmhnall Cam to.[33]

Dun Carloway, a ruinous Iron Age broch.
On his supposed return to Lewis, tradition states Dòmhnall Cam took part in the violent feuds with the Morrisons, and later the Mackenzies. His involvement in the 1605 siege of Stornoway Castle drew the attention of authorities, which resulted an attempt to expel all Macaulays from their lands in Uig. Dòmhnall Cam is traditionally thought to have been buried in Baile na Cille graveyard.[32] Donald played a significant part in the Macaulay's feuds with the Morrisons. One notable Macaulay and Morrison tradition is of a raid conducted by the Morrisons of Ness into Macaulay territory. When the Morrisons drove off cattle belonging to the Macaulays, Dòmhnall Cam, Big Smith and a force of Macaulays pursued the Morrisons into the night, across Loch Roag and finally to Dun Carloway. After killing the sentry, and with his men blocking any exit, Dòmhnall Cam scaled the walls of the broch, aided by two dirks which he slipped between crevices in the stone wall. Once atop the tower Dòmhnall Cam ordered his men to gather large bundles of heather, which he then threw down inside the broch on top of the Morrisons. Dòmhnall Cam then set the heather alight, which smothered and burned the Morrisons to death and in the process also destroyed Dun Carloway.[34][35]