To trepan means to perforate the skull with a drill. Which makes the title of this old folk song from Norwich extremely odd.
However, the song itself isn't actually about parents drilling a hole in the skull of their child, despite the title. Turns out, 'trepan' has another, archaic meaning, which is to trap or ensnare, and that's how it's used here.
But even though it isn't about pediatric brain surgery, it's still quite a dark and violent song.
It's performed below by
. He starts singing the song about halfway through the clip.
Oh, it was my cruel parents that first did me trepan;
They married me to an old man for the sake of money and land.
If they'd married me to a young man without a penny at all,
He'd have took me in his arms and have loved me all the more.
Oh, it's, "Hush, my dearest Nancy, oh, wait 'til we go to town,
I'll buy you a lady's bonney, likewise a mus-e-lin gown;
There is no lady in the land your beauty can compare,
And I'll buy you a little lapdog to follow you everywhere."
"I want none of your little lapdogs nor none of your gentle care;
It's a pity that such an old man my beauty you should snare.
I am not sixteen years of age and scarcely in my bloom;
Oh, you are my cruel torment, both morning, night and noon."
When he comes to bed at night he's as cold as any clay:
His feet are as cold at midnight as corpse, I've heard them say;
His pipes are out of order and his old flute's never in tune:
Oh, I wish that he was dead and a young man in the room.
[Now some they do persuade me to drown him in a well,
And others do persuade me to grind him in a mill.
I'd rather take my own advice and tie him to a stake,]
Oh I'll get a big stick and labour him well, until his bones I break. Source of lyrics