Matthew Armstrong

Mentioned in his father's will on May 06, 1779, as his only son. Implied Armstrong grandsons also listed which implies that Matthew married and had at least five sons. They were given communal funds sufficient for the purpose of buying a black mare from Andrew Leeper, another grandson who was possibly a bit older.

At least according to his father's will, assuming his sons were listed in order, Matthew did not stick strictly to Irish tradition. First son was named James, not Matthew. It's possible he married a non-Scot and that affected things.