Thomas the Rhymer of Erceldoune was at first an object of interest to Scott because of the ballad of _True Thomas_ and the traditions concerning him that floated about the countryside. The "Rhymer's Glen" was afterwards a cherished possession of Scott's own on the Abbotsford estate. In the Advocates' Library at Edinburgh, of which Scott was in 1795 appointed a curator, was an important manuscript that contained among other metrical romances one professing to be a copy of that written by Thomas of Erceldoune on Sir Tristrem. From a careful piecing together of evidence furnished by this poem and by Robert of Brunne, with the assistance of certain legal documents which supplied dates, Scott built up about the old poet a theory that he elaborated in his edition of _Sir Tristrem_, published in 1804, and that continued to interest him vividly as long as he lived. It reappears in many of his critical writings[78] and also in the novels. In the _Bride of Lammermoor_ Ravenswood goes to his death in compliance with the prophecy of Thomas quoted by the superstitious Caleb Balderstone. And in _Castle Dangerous_ Bertram, who is unconvincing perhaps because he is endowed with the literary and antiquarian tastes of a Walter Scott himself, is actuated by an irrepressible desire to discover works of the Rhymer. Scott's edition of _Sir Tristrem_ gives--besides the text, introduction, and notes--a short conclusion written by himself in imitation of the original poet's style. Much of his theory has fallen. He considered this _Sir Tristrem_ to be the first of the written versions of that story, a supposition that was not long tenable. The poem is now known to be based upon a French original, and many scholars think the name Erceldoune was arbitrarily inserted by the English translator; though Mr. McNeill, the latest editor, thinks there is a "reasonable probability" in favor of Scott's opinion that the author was the historic Thomas, who flourished in the thirteenth century. It is important, however, that Scott's scholarship in the matter passed muster at that time with such men as Ellis, who wrote the review in the _Edinburgh_, in which he said, "Upon the whole we are much disposed to adopt the general inferences drawn by Mr. Scott from his authorities, and have great pleasure in bearing testimony to the very uncommon diligence which he has evinced in collecting curious materials, and to the taste and sagacity with which he has employed them.... With regard to the notes, they contain an almost infinite variety of curious information, which had been hitherto unknown or unnoticed."[79] John Hookham Frere said, as quoted in a letter by Ellis, "I consider _Sir Tristrem_ as by far the most interesting work that has as yet been published on the subject of our earliest poets."[80] Scott's opinions were in 1824 thought to be of sufficient importance, either from their own merits or on account of his later fame, to call forth a dissertation appended to the edition of