I set out the version I transcribed like this. See above for my note on punctuation.

Garry

Prince Heathen
Sung by Martin Carthy on Prince Heathen (1969). A second recording, re-released on The Martin Carthy Chronicles (2001), was taken from a previously unreleased radio session from 1974, from John Peel's "Top Gear" BBC radio show. A third recording was made for Signs of Life (1998). The lyrics vary between the three recordings in only tiny details.
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Lady sits in her garden fair
Sewing a silken seam
And by there come this Prince Heathen
And he vowed her love he'd gain

O lady will you weep for me
Lady tell me true
Oh never yet you heathen dog
I never shall for you

She turned her around and aloud did cry
Begone I love not you
And then he vowed him Prince Heathen
That she would weep full sore

O lady will you weep for me
Lady tell me true
Oh never yet you heathen dog
I never shall for you

So he's laid her all on the ground
Between himself and the wall
And there he's stripped her of her will
And her maidenhead and all

O lady will you weep for me
Lady tell me true
Oh never yet you heathen dog
I never shall for you

Oh I slew your father in his bed
And your mother by his side
And your seven brothers one by one
I drowned them in the tide

O lady will you weep for me
Lady tell me true
Oh never yet you heathen dog
I never shall for you

Oh I'll lay you in a vault of stone
With thirty locks upon
And meat nor drink you will never get
Till your baby it is born

O lady will you weep for me
Lady tell me true
Oh never yet you heathen dog
I never shall for you

So he's laid her in a vault of stone
With thirty locks upon
And he's taken the key in his right hand
To the mountain he has gone

O lady will you weep for me
Lady tell me true
Oh never yet you heathen dog
I never shall for you

Prince Heathen he from the mountains came
With his merry men all in a line
And he sought out this fair young maid
Down in her vault of stone

And how d'you do and do you weep
Lady tell me true
I'm never weeping heathen dog
But dying here for you

Oh meat nor drink you'll never get
Nor out of prison come
Oh meat nor drink you will never get
Till your baby it is born

O lady will you weep for me
Lady tell me true
Ah never yet you heathen dog
I never shall for you

Her time came on and further on
In labour there she lay
She laboured up she laboured down
But lighter she could not be

O lady will you weep for me
Lady tell me true
Ah never yet you heathen dog
And never yet for you

So he's laid her all on the green
And his merry men stood around
And how they laughed and how they mocked
As she brought forth a son

O lady will you weep for me
Lady tell me true
Ah never yet you heathen dog
I never shall for you

A drink a drink the young girl cries
All from Prince Heathen's hand
Oh never a drop Prince Heathen cries
Till ye give up your son

Then lend to me a silken shawl
Or a blanket or a sheet
That I may wrap this little baby
That lies in me arms asleep

Oh I'll lend you an old horse blanket
To wrap him head and feet
And there she took it in her hand
So bitter she did weep

O lady do you weep for me
Lady tell me true
Oh never yet you heathen dog
And never now for you

Could you not give any better thing
Than a horse blanket or a sheet
To wrap and swaddle your own young son
That lies in my arms asleep

He's borne her up so very soft
Borne her up so slow
He's laid her down in a soft green bed
So dearly he loved her now

O lady will you weep for me
Lady tell me true
Ah never yet you heathen dog
I never shall for you
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New: 12 February 2000
Now: 31 March 2001
Child #104. Transcribed by Garry Gillard. The transcription was originally of the Prince Heathen performance, but in a few places I have changed it to follow Martin Carthy's later preferences, in Signs of Life, where they make the sense clearer.