The Closed Book by William le Queux

The low-lying island upon which we found ourselves was certainly a dismal, out-of-the-world place, covered by rank grass and nettles, and yellow with St John's wort. Ruined walls were scattered around the castle of Threave itself, a square, roofless tower, which in the bleakness of its gaunt and terrible majesty suggested the idea of an armed skeleton, in the facial apertures of which lay the darkness of death and decay.

This was the monument of the Douglases' pride and the engine of their oppression during their galling ascendancy, when Archibald rode with his retinue of two thousand armed retainers, many of them the most noted desperadoes, and ravaged the Border. The huge fourteenth-century fortress, once the pride of kings, was still a massive pile, with walls nearly seventy feet high, built of common grey moor stone.