Second son of the Armstrong chief at Mangerton, John ‘Johnnie’ Armstrong of Gilnockie became de facto head of his clan. Johnnie was a particularly notorious Border reiver, leading a band of around one-hundred and sixty men on raids into England, and against fellow Border houses during the 16th century. The Armstrongs were one of, if not the most powerful clans in the region known as the ‘Debatable Lands’, and Johnnie a much-romanticised folk-hero of that realm. He ran an operation one might nowadays call a protection racket, and was for that reason a constant thorn in the side of the Barons of the Scottish Borders.
Perhaps extending his reign of banditry a stretch too far, Johnnie Armstrong of Gilnockie burned Netherby in Cumbernauld in 1527. In retaliation, William Dacre, 3rd Baron Dacre, had the Armstrongs towers around Canonbie burned the following year. Furthermore, the Archbishop of Glasgow (and Chancellor of Scotland) formally excommunicated Johnnie, in an attempt to quell the lawlessness of the Borders, and better heal diplomatic ties with England. In 1530, Johnnie Armstrong was summoned to Caerlenrig Chapel (now Teviothead) to meet with the young and newly ascended King James V. He was promised leniency should he submit to the king. Alas, the summons was a trap, and Johnnie Armstrong, along with a large number of his men (sources state either twenty-four or forty-eight), was there hanged.
The execution of Johnnie Armstrong was deemed by most Borderers an unforgivable betrayal by the crown; leaving a stain on King James V’s reputation, and creating a deep sense of indignation and resentment which pervaded in the ‘Debatable Lands’ for many generations. Johnnie’s life and death were immortalised by ‘The Ballad of Johnnie Armstrong’, popularised in the 19th century by its inclusion in Sir Walter Scott’s Minstrelsy of the Scottish Border.