I will deal with the external evidence first. Practically it amounts to this: (1) that Lady Granville knew that her mother, the Duchess of Devonshire, dramatized Miss Lee's Kruitzner; and (2) that Lady Georgiana Fullerton believed that the duchess gave the MS. of her play to Lady Caroline Ponsonby, and that, many years after, Lady Caroline handed it over to Byron.
The external evidence establishes the fact that the Duchess of Devonshire dramatized Kruitzner, but it does not prove that Byron purloined her adaptation. It records an unverified impression on the part of the duchess's granddaughter, that the MS. of a play written between the years 1801-1806, passed into Byron's hands about the year 1813; that he took a copy of the MS.; and that in 1821-22 he caused his copy to be retranscribed and published under his own name.
But Mr. Leveson Gower appeals to internal as well as external evidence, (1) He regards the great inferiority of Werner to Byron's published plays, and to the genuine (hitherto) unpublished first act, together with the wholesale plagiarisms from Miss Lee's story, as an additional proof that the work was none of his. (2) He notes, as a suspicious circumstance, that "while the rough copies of his other poems have been preserved, no rough copy of Werner is to be found."
In conclusion, he deals with two possible objections which may be brought against his theory: (1) that Byron would not have incurred the risk of detection at the hands of the owners of the duchess's MS.; and (2) that a great poet of assured fame and reputation could have had no possible motive for perpetrating a literary fraud. The first objection he answers by assuming that Byron would have counted on the reluctance of the "Ponsonby family and the daughters of the Duchess" to rake up the ashes of old scandals; the second, by pointing out that, in 1822, he was making "frantic endeavours to obtain money, not for himself, but to help the cause of Greece."
(1) With regard to the marked inferiority of Werner to Byron's other plays, and the relative proportion of adapted to original matter, Mr. Leveson Gower appears to have been misled by the disingenuous criticism of Maginn and other contemporary reviewers (vide the Introduction, etc., [p. 326]). There is no such inferiority, and the plagiarisms, which were duly acknowledged, are confined to certain limited portions of the play. (2) There is nothing unusual in the fact that the rough draft of Werner cannot be found. In fact, but few of the early drafts of the dramas and other poems written in the later Italian days ever reached Murray's hands, or are still in existence. The fair copy for the printer alone was sent home. The time had gone by when Byron's publisher, who was also his friend, would stipulate that "all the original MSS., copies and scraps" should fall to his share. But no argument can be founded on so insignificant a circumstance.
Finally, the argument on which Mr. Leveson Gower dwells at some length, that Byron's "motive" for perpetrating a literary fraud was the necessity for raising money for the cause of Greek independence, is refuted by the fact that Werner was begun in December, 1821, and finished in January, 1822, and that it was not till the spring of 1823 that he was elected a member of the Greek Committee, or had any occasion to raise funds for the maintenance of troops or the general expenses of the war. So far from attempting to raise money by Werner, in letters to Murray, dated March 6, October 24, November 18, 1822, he emphatically waives the question of "terms," and makes no demand or request for money whatever. It was not till December 23, 1823 (Letters, 1901, vi. 287), two years after the play had been written, that he speaks of applying the two or three hundred pounds which the copyright of Werner might be worth, to the maintenance of armed men in the service of the Provisional Government. He could not have "purloined" and palmed off as his own the duchess's version of Miss Lee's story in order to raise money for a purpose which had not arisen. He had no intention at first or last of presenting the copyright of Werner to Murray or Hunt, but he was willing to wait for his money, and had no motive for raising funds by an illegal and dishonourable trick.
That Byron did not write Werner is, surely, non-proven on the external and internal evidence adduced by Mr. Leveson Gower. On the other hand, there is abundant evidence, both external and internal, that, apart from his acknowledged indebtedness to Miss Lee's story, he did write Werner.
To take the external evidence first. On the first page of Mrs. Shelley's transcript of Werner, Byron inserted the date, "Dec. 18, 1821," and on the last he wrote "[The End] of fifth act of the Drama. B. P[isa]. Jy 21. 1822."
Turning to the journal of Edward Williams (Shelley's Prose Works, 1880, iv. 318), I find the following entries:—
"December 21, 1821. Lord B. told me that he had commenced a tragedy from Miss Lee's German Tale ('Werner'), and had been fagging at it all day."