I had the name "Tom O'Bedlam" sitting in my head, and decided to look it up. Upon talking to atesh, he told me I was right, there was a song called "Tom O'Bedlam," not unlike "Thomas the Rhymer" and "Tam Lin." (Tam=Tom). Tom the man driven insane by the fairies.

I realized I had the name stuck in my head because I went to see King Lear recently:

Edmund
Tut, I should have been that I am,
had the maidenliest star in the firmament twinkled 135
on my bastardizing. Edgar--

Enter EDGAR.

and pat he comes like the catastrophe of the old
comedy: my cue is villanous melancholy, with a sigh
like Tom o' Bedlam. O, these eclipses do portend
these divisions! fa, sol, la, mi.

--King Lear : Act 1, Scene 2

Then when Edgar decides he must go into hiding to spare his life, he takes on the persona of Tom O'Bedlam:

EDGAR
I heard myself proclaim'd;
And by the happy hollow of a tree
Escaped the hunt. No port is free; no place,
That guard, and most unusual vigilance,
Does not attend my taking. Whiles I may 'scape,
I will preserve myself: and am bethought
To take the basest and most poorest shape
That ever penury, in contempt of man,
Brought near to beast: my face I'll grime with filth;
Blanket my loins: elf all my hair in knots;
And with presented nakedness out-face
The winds and persecutions of the sky.
The country gives me proof and precedent
Of Bedlam beggars, who, with roaring voices,
Strike in their numb'd and mortified bare arms
Pins, wooden pricks, nails, sprigs of rosemary;
And with this horrible object, from low farms,
Poor pelting villages, sheep-cotes, and mills,
Sometime with lunatic bans, sometime with prayers,
Enforce their charity. Poor Turlygod! poor Tom!
That's something yet: Edgar I nothing am.

--King Lear : Act 2, Scene 2

Tom O'Bedlam's Song

For to see Mad Tom of Bedlam
Ten thousand miles I traveled
Mad Maudlin goes on dirty toes
To save her shoes from gravel.

Chorus

Still I sing bonny boys, bonny mad boys
Bedlam boys are bonny
For they all go bare and they live by the air

And they want no drink nor money.

I went down to Satan's kitchen
To break my fast one morning
And there I got souls piping hot
All on the spit a-turning.

There I took a cauldron
Where boiled ten thousand harlots
Though full of flame I drank the same
To the health of all such varlets.

My staff has murdered giants
My bag a long knife carries
To cut mince pies from children's thighs
For which to feed the fairies.

No gypsy, slut or doxy
Shall win my mad Tom from me
I'll weep all night, with stars I'll fight
The fray shall well become me.

From the hag and hungry goblin
That into rags would rend ye,
All the sprites that stand by the naked man
In the book of moons, defend ye.

That of your five sound senses
You never be forsaken,
Nor wander from your selves with Tom
Abroad to beg your bacon.

With a thought I took for Maudlin,
And a cruse of cockle pottage,
With a thing thus tall, Sky bless you all,
I befell into this dotage.

I slept not since the Conquest,
Till then I never waked,
Till the naked boy of love where I lay
Me found and stript me naked.

I know more than Apollo,
For oft when he lies sleeping
I see the stars at mortal wars
In the wounded welkin weeping.

The moon embrace her shepherd,
And the queen of love her warrior,
While the first doth horn the star of morn,
And the next the heavenly farrier.

The moon's my constant mistress,
And the lonely owl my marrow;
The flaming drake and the night crow make
Me music to my sorrow.

The spirits white as lightening
Would on my travels guide me
The stars would shake and the moon would quake
Whenever they espied me.

And then that I'll be murdering
The Man in the Moon to the powder
His staff I'll break, his dog I'll shake
And there'll howl no demon louder.

With a host of furious fancies,
Whereof I am commander,
With a burning spear and a horse of air
To the wilderness I wander.

By a knight of ghosts and shadows
I summoned am to tourney
Ten leagues beyond the wide world's end-
Methinks it is no journey.

That of your five sound senses
You never be forsaken,
Nor wander from your selves with Tom
Abroad to beg your bacon.

I now reprent that ever
Poor Tom was so disdain-ed
My wits are lost since him I crossed
Which makes me thus go chained

So drink to Tom of Bedlam
Go fill the seas in barrels
I'll drink it all, well brewed with gall
And maudlin drunk I'll quarrel

Still I sing bonny boys, bonny mad boys
Bedlam boys are bonny
For they all go bare and they live by the air

And they want no drink nor money.