I'm looking for some history to the song. I've discovered that James Thompson (1700-1748)/David Mallet was the originator of the words in their play Alfred. The air was written by Dr. Thomas Arne.

The words were adapted into the sea shanty The Mermaid (in DT) or Married to a Mermaid:

There was a gay young farmer,
Who liv'd on Salisbury plain;
He lov'd a rich Knight's daughter dear!
And she lov'd him again.
The Knight he was distressed,
That they should sweethearts be.
So he had the farmer soon pressed,
And sent him off to sea.

Singing Rule Britannia,
Britannia rule the waves
Britons never, never, never shall be slaves...

'Twas on the deep Atlantic,
Midst Equinoctial gales;
This young farmer fell overboard
Among the sharks and whales;
He disappeared so quickly,
So headlong down went he,
that he went out of sight like a streak of light
to the bottom of the deep blue sea.

Singing Rule Britannia,
Britannia rule the waves
Britons never, never, never shall be slaves...

We lowered a boat to find him,
We thought to see his corse,
When up to the top he came with a bang,
And sang in a voice so hoarse,
'My comrades and my messmates,
Oh, do not weep for me,
For I'm married to a mermaid,
At the bottom of the deep blue sea.'

Singing Rule Britannia,
Britannia rule the waves
Britons never, never, never shall be slaves...

He said that as he went down,
Great fishes he did see;
They seemed to think as he did wink,
That he was rather free.
But down he went so quickly,
Saying, ''Tis all up with me,'
When he met a lovely mermaid
At the bottom of the deep blue sea.

Singing Rule Britannia,
Britannia rule the waves
Britons never, never, never shall be slaves...

She came at once unto him,
And gave him her white band,
Saying, 'I have waited long, my dear,
To welcome you to land.
Go to your ship and tell them,
You'll leave them all for me;
For you're married to a mermaid
At the bottom of the deep blue sea.'

Singing Rule Britannia,
Britannia rule the waves
Britons never, never, never shall be slaves...

The wind was fair, the sails set,
The ship was running free;
When we all went to the captain bold,
And told what we did see.
He went unto the ship's side,
And loudly bellowed he,
'Be happy as you can, my man,
At the bottom of the deep blue sea.'

Singing Rule Britannia,
Britannia rule the waves
Britons never, never, never shall be slaves...


Here are the words to Rule Britannia:

When Britain first, at Heaven's command
Arose from out the azure main;
Arose from out the azure main;
This was the charter, the charter of the land,
And guardian angels sang this strain:

Chorus
Rule Britannia! Britannia rules the waves
Britons never, never, never shall be slaves.

The nations, not so blest as thee
Must, in their turns to tyrants fall
Must, in their turns to tyrants fall
While thou shalt flourish, shalt flourish great and free
The dread and envy of them all.
(Chorus)

Still more majestic shalt thou rise
More dreadful from each foreign stroke
More dreadful from each foreign stroke
As the loud blast, the blast that tears the skies
Serves but to root thy native oak.
(Chorus)

Thee haughty tyrants ne'er shall tame
All their attempts to bend thee down
All their attempts to bend thee down
Will but arouse, arouse thy generous flame
But work their woe, and thy renown.
(Chorus)

To thee belongs the rural reign
Thy cities shall with commerce shine
Thy ci-ties shall with commerce shine
All thine shall be, shall be the subject main
And every shore it circles thine.
(Chorus)

The Muses, still with freedom found
Shall to thy happy coast repair
Shall to thy happy coast repair
Blest isle with matchless, with matchless beauty crowned
And manly hearts to guard the fair.
(Chorus)
^^

There's no information in Hugill, Whall, Shay or Doerflinger - at least under those titles. I'm curious to know if there's anything information about the shanty -when it became popular in that form - that sort of thing... Of course there's probably no exact telling - but surely someone must have speculated!

As always, thanks!