Hi,

The oldest extant version is "The False Knight Outwitted: A New Song" which is Child 4F, from Roxburghe Ballads, III, 449. In the catalogue of the British Museum it's listed "London? 1710?" A reprint date of 1780 is confirmed. There's no narrative introduction and it has an abbreviated ending with the "parrot" stanzas. The girl's name is "pretty Polly." It may be viewed online here: http://ebba.english.ucsb.edu/ballad/31135/transcription

1    'Go fetch me some of your father's gold,
And some of your mother's fee,
And I'll carry you into the north land,
And there I'll marry thee.'

2    She fetchd him some of her father's gold,
And some of her mother's fee;
She carried him into the stable,
Where horses stood thirty and three.

3    She leapd on a milk-white steed,
And he on a dapple-grey;
They rode til they came to a fair river's side,
Three hours before it was day.

4    'O light, O light, you lady gay,
O light with speed, I say,
For six knight's daughters have I drowned here,
And you the seventh must be.'

5    'Go fetch the sickle, to crop the nettle
That grows so near the brim,
For fear it should tangle my golden locks,
Or freckle my milk-white skin.'

6    He fetchd the sickle, to crop the nettle
That grows so near the brim,
And with all the strength that pretty Polly had
She pushd the false knight in.

7    'Swim on, swim on, thou false knight,
And there bewail thy doom,
For I don't think thy cloathing too good
To lie in a watry tomb.'

8    She leaped on her milk-white steed,
She led the dapple grey;
She rid till she came to her father's house,
Three hours before it was day.

9    'Who knocked so loudly at the ring?'
The parrot he did say;
'O where have you been, my pretty Polly,
All this long summer's day?'

10    'O hold your tongue, parrot,
Tell you no tales of me;
Your cage shall be made of beaten gold,
Which is now made of a tree.'

11    O then bespoke her father dear,
As he on his bed did lay:
'O what is the matter, my parrot,
That you speak before it is day?'

12    'The cat's at my cage, master,
And sorely frighted me,
And I calld down my Polly
To take the cat away.'