The earliest recipe I’ve found for sauce Espagnole is in François Massialot’s Cuisinier Royal et Bourgeois which first appeared in 1691 – the edition is from 1705, but there wasn’t a revised edition until 1712. Massialot’s appears under the recipe “Perdrix sausse à L’Espagnole” or Partridge sauce Espagnole and calls for Burgundy wine, partridge and partridge liver, ham essence, truffles, onion, garlic and clove.
The anonymous author of Le Cuisinier Gascon is the next with a recipe (though Menon mentions Sauce Espagnole a few times and, like La Varenne in his Le Cuisinier François (1651), he has a recipe for the somewhat similar Sauce Robert) which is similar but subtracts the truffles, liver (ironically because the Gascon author is insane about foie gras) clove and garlic, and adds veal, shallots, coriander and carrots, and swaps Champagne for the Burgundy.
Audot in his Cuisiniere de la Campagne of 1832 helpfully suggests that you make it after a party when you have a bunch of fowl and game birds lying around to make the sauce. His is substantially similar but doesn’t speciifically mention partridge and uses white wine, mushrooms and flour (the beginning of attempts to thicken the sauce).
But the master, Antonin Carême does use partridge, with what is still the classic (if hardly used) recipe – he also codified the steps, omitted the wine, and added a roux [reduce veal and partridge to a residue, add residue to stock and remaining ingredients, reduce, skim, etc.] In addition, he officially made this brown sauce one of the 5 “Mother Sauces” that give birth to all the other secondary and tertiary sauces in the French Pantheon.
Escoffier’s final revision removes the meat and replaces the vegetables with a mirepoix (a vegetable, and sometimes ham, essence) and a significant amount of tomato paste – this is the Espagnole, or brown sauce, that is used to make the now more common demi-glace. The meatliness of the Espagnole being now but a memory, Escoffier gives instructions for making a “Lenten Espagnole” with fish fumet.
These days, it’s difficult to find a recipe that includes the partridge that started it all.