Specifically, the monument commemorates Robert Walter Stuart, the 11th Lord Blantyre. He died on the 22nd of September 1830: he was shot when he looked out from an upper window of a hotel in Brussels, during what later came to be known as the Belgian Revolution.
As the New Statistical Account (1845) observes, "he was Lord Lieutenant of Renfrewshire, and was so highly esteemed by the gentlemen of that county that, shortly after his death, they erected, on a conspicuous situation on his estate of Erskine, an elegant column in the form of an obelisk, as a tribute of respect to his memory."
The obelisk is about 80 feet high, and it was erected within a few years of Lord Blantyre's death. The architect was William Burn, who had been a pupil of Robert Smirke (the architect of nearby Erskine House, which was built for Lord Blantyre, though his untimely death meant that he would not live to enjoy it).
For the inscription, see
NS4471 : Monument to Lord Blantyre: inscription and
NS4471 : Robert Walter 11th lord Blantyre Bishopton.
For other views of the monument as a whole, see
NS4472 : Monument near Bishopton,
NS4471 : Monument to Robert Walter, 11th Lord Blantyre and
NS4471 : Blantyre Monument.
Charles Walter Stuart, son of Robert Walter Stuart, became the 12th Lord Blantyre, but the title became extinct on his death; he had been predeceased by his only son. The family were originally of the Stuarts (or Stewarts) of Minto; the first Lord Blantyre was Walter Stuart, elevated to the peerage in 1606. See discussion at
NS4863 : Paisley Abbey: the Cardonald Stone.
(The OS grid line almost coincides with the north face of the obelisk; most or all of the monument is therefore in the same grid square as the photographer, as is most of its surrounding enclosure.)