Taken from http://www.arrocharheritage.com, an excellent website packed with historical information covering Arrochar, Tarbet and Ardlui.
Ardlui shows evidence of wild lawless days lying at the boundary of the ancient kingdoms of Strathclyde, Dalriada and Pictland battles and clashes must have been common in this area. Clach na Bhreatuinn, Stone of The Briton, marks the scene of a great battle between the Briton and the Western Scots in the year 717. More evidence of this is the stone burial cairn in the field below Stuckendroin – it creates an intriguing atmosphere of what may have gone on in these dark days.
Nestled at the bottom of Glenfalloch, which in the Macfarlane days was the boundary of the barony of Arrochar on the north, the glen created a natural pass for the people of Atholl onto Arrochar on their way to the lower grounds in Monteith and Stirling. This would have been a natural battle field for the MacFarlanes and those who tried to use it. Other areas of interest include On the Eilean–a-vow, Alms House, Pulpit Rock and the Pier.
From the Ordnance Gazetteer of Scotland (1882-4)
Ardlui, a locality in Arrochar parish, Dumbartonshire, at the influx of Falloch Water to the head of Loch Lomond, 8 miles N of Tarbet. It has an hotel and a small pier where the Loch Lomond steamers lie; and it communicates by coach with Crianlarich station. The tract around it is a small expanse of rich low strath; the hills around it are covered with foliage, and streaked with torrents or waterfalls; the mountains in the distance sweep round the horizon, in a curving series of alpine peaks; and the whole scene is a most diversified, picturesque, sublime amphitheatre. Ardlui House stands near the water, and is a recent erection.
(F.H. Groome, Ordnance Gazetteer of Scotland (1882-4); © 2004 Gazetteer for Scotland)