"Historians debate whether the potato was primarily a cause or an effect of the huge population boom in industrial-era England and Wales. Prior to 1800, the English diet had consisted primarily of meat, supplemented by bread, butter and cheese." Discussion about potato-and-population and which came first (that's a duh thing: once people started eating potatoes and, more relevantly, feeding them to their very small children when they were weaning them, the kids quit dying the way they used to and there were a lot more people running around. Simple.)
In any event, that makes the wikipedia entry on cottage pie...misleading:
"The term cottage pie is known to have been in use in 1791, when potato was being introduced as an edible crop affordable for the poor (cf. "cottage" meaning a modest dwelling for rural workers)."
Sure, some parson named James Woodford kept a diary and kept mentioning how dinner was cottage-pye and roast something or other, but there's _zero_ reason to believe that the cottage-pye he was eating had anything at all to do with potatoes. If I had to guess, I'd say Woodford's dinner involved a double-crust containing whatever was leftover from the previous day, chopped up with gravy added. But I'm just guessing.
"In early cookery books, the dish was a means of using leftover roasted meat of any kind, and the pie dish was lined with mashed potato as well as having a mashed potato crust on top."
By "early", they mean 50-60 years later, and the dishes were called things like "A casserole of" whatever (Miss Leslie at mid-century) or "cold meat cookery"/"baked" whatever 60-70 years later.
I'm not calling this thing cottage pie any more. And I'm not making china pie (I expect to be eating my words on this at some point, because R. seems pretty committed to having that again). I'm just going to call it that meat and potatoes thing, until I quit being so annoyed at poorly executed food history.
Somehow, I am not surprised to learn that there's a variant called Cumberland Pie that adds another layer on top, of cheese and/or bread crumbs.