At the risk of take it to the sheep thread, Hoss...
In the Medieval era, sheep were bred mostly for wool - it was the heart of the English economy, hence the ‘woolsack’ on which the speaker of the House of Commons sits (found to actually be stuffed with horsehair some time in the c19/c20).
In the 18th century, this changed to the meat being the most valuable portion, and sheep were selectively bred to find a meatier carcass.
In particular, Robert Bakewell(?) bred the “dishley leicester” a sheep with a particularly prime build. It was especially meaty.
The dishley Leicester lives on in weird looking breeds such as the border Leicester
And the blue faced Leicester.
.
Sheep breeding developed a pyramid structure where hardy and maternal upland sheep like mine would be crossed with a Leicester ram to make eiether a mule (blue face) or halfbreed (border), with the qualities of the mother and the frame of the ram. Then a second cross would be done between the mule ewes and a “down breed” - a squatter meatier lowland sheep, to give the final commercial lamb destined for prime cuts.
(Southdown)
In recent years, continental rams like the texel or the beltex have become common in this second ‘terminal sire’ position, for their extreme meatiness. They’re ugly as hell though.
beltex
As the meat has become more specialised, the value of the wool has fallen, to the extent that a modern sheep costs more to shear than you get for the fleece.
So there’s more to the square sheep portrait than just a bad painter.