[2] By tradition, the Armstrongs followed the cause of Robert the Bruce in the Scottish Wars of Independence, and their recorded relationship with the crown was certainly more straightforwardly loyal in the fourteenth century than in later periods.

Alexander Armstrong, second laird of Mangerton was imprisoned and killed by the anti-Bruce conspirator William de Soulis at Hermitage Castle.

[3] Gilbert Armstrong, served as steward of the household of David II of Scotland, Master of the Horse to the king, and ambassador to England in 1363.

[2] Sir Adam Armstrong was listed in 1374 as one of the knights permitted to travel outside Scotland with the Earl of March and Dunbar, then the principal defender of the Scottish border.

In 1398, Alexander, David and Geoffrey Armstrong committed their signatures as 'borowis' for the third Earl of Douglas in pledging to keep the peace on the border.

[2] Curiously, despite their tense relationship with the Stewart crown, a number of Armstrongs are recorded as officers in the royalist armies serving Charles I in the Wars of the Three Kingdoms.

[7] William ("Christie's Will") Armstrong, perhaps the last of the clan's famous border freebooters, also fought for the crown as a servant of the earl of Traquair.

However, Armstrong has been historically associated with the Ulster Gaelic name, Mac Tréan-Labhraidh, a branch of the Ó Labhradha family.