It appears to me (not an expert) that cultures that experience winter all seem to have some sort of midwinter celebrations. Perhaps there’s a human need to push back against the dark and cold.
I’m reasonably familiar with most of the Shakespearean plays but don’t recall such a stage direction. Shakespeare’s plays are for the most part completely devoid of stage directions, except for the famous “Exit, pursued by a bear” in The Winter’s Tale. In Cymbeline there are two Welsh characters. The one time I saw it performed at the Oregon Shakespeare Festival, the actors spoke with Scottish accents, either because it was too difficult for the actors to manage Welsh accents, or, more likely, because the director assumed the US audience wouldn’t recognize a Welsh accent.
Everything read aloud in Welsh is a miracle, is what it is. 
I’ll try to make this the last time I use this:
Dave Barry says the Welsh language had all its vowels stolen by the Vikings, so now when parents sing, “Old MacDonald,” to their children and come to, “E-I-E-I-O,” they just lapse into sad silence.
I wonder if there is any connection between the Welsh Mari Lwyd and the Norse nithing pole.
I’d never heard of it, but I’m, uh, trying to get back into gaming a bit?, and am currently playing Assasins’ Creed: Valhalla, and I’m kind of getting a Halloween vibe from Mari Lwyd, rather than a Christmas vibe.
I’m to tired to go down a Wikipedia rabbit hole right now.
Anyone who is interested in these themes might enjoy Off With His Head! by Ngaio Marsh (Death of a Fool in the UK, I understand.)
Set at the Winter Solstice, appropriately enough for this discussion.
Wow, i haven’t read any of her books in, gee, decades!
I’ve occasionally wondered if this was where whoever it was got the idea for the stage name of the music-hall singer Marie Lloyd, even though she was a Londoner born and bred.
Nadolig Llawen!