By which wee note the fairies
Were of the old profession:
Their songs were Ave Maries,
Their dances were procession.
But now, alas! they all are dead,
Or gone beyond the seas,
Or farther for religion fled,
Or else they take their ease.
This morning I was reminded of this by a gloss in for the June Eclogue of Spenser's Shepheardes Calendar (1579), which gives a rather eccentric etymology for the word "elfes" as deriving from the Guelfes (as in the Guelphs of Florence - suitably Italianate and scheming), and adds moreover that they are the invention of "bald Friers and knavish shavelings", designed to distract the common people from the falsehood of the Catholic religion.
A couple of things strike me here. One is a Chaucerian echo: the association of Friars and Fay also crops up at the beginning of the Wife of Bath's tale:
I speke of manye hundred yeres ago.
But now kan no man se none elves mo,
For now the grete charitee and prayeres
Of lymytours and othere hooly freres,
That serchen every lond and every streem,
As thikke as motes in the sonne-beem,
That shouldn't surprise us, if Spenser was indeed the author of his own notes to the Calendar, since he was a big Chaucer fanboy, although whereas he associates friars and fairies, Chaucer gives us friars as the fairies' mundane replacement. But that brings us to the other point, which is that the elves are always in the past. If friars are currently plentiful, fairies came before friars; if the monasteries have just been dissolved and the friaries fried, then the fairies turn Catholic.
Even at this date, they are also associated with what John Clute calls a "thinning" of the world. "For oh, for oh, the hobbyhorse is forgot!", as the possibly-recusant Shakespeare has more than one character say, while Spenser himself in the May eclogue tussles (in the persons of a tolerant and a strict shepherd named Palinode and Piers) over his feelings about May Day festivities. The world has been left a more prosaic place by the passing of such things - at least, until Spenser finds a way to bring Faerie and St George triumphantly back home in Protestant guise in 1590.
Kipling put much of that feeling into "Dymchurch Flit", which is where I came in with the other post. Kipling assumes that the fairies have gone abroad - "beyond the seas" in Corbett's phrase - a tradition continued by the Catholic Tolkien at the end of The Lord of the Rings. But Kipling also made room for another tradition, which is that the fairies went into exile not abroad but at home, simply slipping from human sight. I think I first came across this idea circa 1976, while listening to the Horslips album The Book of Invasions (and particularly the track "Sideways to the Sun"), though after that I found it everywhere. Ousted by the Milesians, the Tuatha Dé Danann take up a second career as the Sidhe, shunting the poor old Fir Bolg even further down the line into obscurity. Magic helps in this kind of move, but there is a magic-free version of the same idea, which gives rise to Kipling's "Dark People", the small-statured, pre-Celtic, aboriginal inhabitants of Britain, whose lives consist mainly of crouching in the heather and licking trees for their delicious moss. What magic did for the Tuatha, the Dark People do for themselves through stealth and woodcraft. These people featured in Rosemary Sutcliff too - although whether she got the idea from Kipling or elsewhere I'm not sure. The whole '"Waves of Invasion Each One Displacing the Last" meme was popular at the time - and is also of course the basis for Diana Wynne Jones's Power of Three. On reflection I'm not sure whether either Kipling or Sutcliff actually says that the Dark People are the origin of fairy beliefs - and indeed in Kipling's case it would be difficult, since he gives a different explanation as well - or whether I just heard it floating by on the Zeitgeist.
It occurs to me just now that this is all probably in Diane Purkiss or Jeremy Harte, but since I've maundered so long, I will let it stand.