greensauce owing its colour to green leaves, especially of sorrel, has a very long history, and an international one. Something of the sort may well date back to classical times and was apparent in medieval cookery in various parts of Europe.
In England, the earliest recipes or descriptions for the sauce call for a complex mixture of green herbs. Constance Hieatt (1982) cites the 12th-century De Utensilibus of Alexander Neckham, who includes among the ingredients sage, parsley, dittany (see dittander), thyme, garlic, salt, and pepper. Jennifer Stead (1979) refers to various others, from the 14th century onwards, including Henry Buttes (1599), who said that greensauce was ‘made of sweete hearbes … a clowe or two, and a little Garlicke’, and Hannah Glasse (1747), whose recipe for roast ‘green’ (young) goose has sorrel as the only or main greenstuff for the accompanying ‘green Sauce’. Jennifer Stead also shows how widespread in England was the use of ‘greensauce’ as the name for sorrel, observing that Geoffrey Grigson (1955) lists eleven English counties where this name was used. In addition, she quotes Yorkshire dialect dictionaries of the 19th century to good effect, e.g. Easther (1883):
Greensauce: the plant Sorrel, Rumex acetosa, called also by some saar grass (sour grass), much used formerly as a sauce with meat, especially veal. When the Rev. J. Paine entered on the occupancy of Woodlands Grove, Dewsbury Moor, about 1829, there was in the garden a long row of cultivated sorrel of a superior quality. In the dining room … was a box seat, or locker which contained a large heavy ball. This was pointed out to the incomers as to be used for crushing the greensauce, which was customarily placed in a large bowl, and the ball rolled about upon it. One of my informants says, ‘About fifty years ago every garden had its greensauce. It was very common then to have cofe [calf] feet boiled, and the green-sauce was used with them; also “amang sallit”. ’