Constable took trouble over The Hay Wain. He made a small sketch in oils and a full size sketch in oils. The former lives at The Yale Center and the latter in the V&A. Actually he did this for all his big landscapes.
This is a once in a lifetime opportunity to see The Hay Wain and both sketches at The National Gallery until 2nd February next year in a small exhibition: Discover Constable & The Hay Wain. Today it is hard to believe that when it was exhibited at the Royal Academy in 1821 it went unsold. Not a profit in his own country.
It had to cross the Channel to achieve recognition, winning a gold medal at the 1824 Paris Salon. Stendhal (Le Rouge et le Noir) observed: “We have never seen anything like these pictures before. It is their truthfulness that is so striking.” I am not sure what he means, perhaps it is the realism of the composition of horses, wagon and driver and the naturalistic depiction of the landscape in which they are set. What I am sure about is the profound influence it had on French landscape painting for more than fifty years, leading to Impressionism in the 1870s.
The examples below illustrate this, as well as showing how many great French pictures hang in American galleries. They are in chronological order and the second Corot, 1865 – 1870, is early Impressionism.
It is indeed a focused exhibition well worth seeing — thank you for the recommendation.
There is a book out (have ordered, but not yet recieved) that purports to answer the question and suggests you are right: “The key to the revolution effected by Constable in European art was his demonstration of how mundane activities in particular places could be depicted in heroic terms.”
That line is from one of the rather positive reviews that suggest the book is a breath of fresh air:
https://literaryreview.co.uk/the-wright-stuff
(To read less: a shorter review came out in *Country Life* in the 8 Oct. issue, in which there is also an article by the author, himself, setting out some of the key themes of the book.)