"In working on an edition of Swinburne's correspondence, I have in the last several years discovered two previously unknown poems by Algernon Charles Swinburne. One has existed for decades in the British Library's Ashley Collection, unrecognized probably because it survives in the form of a copy not in Swinburne's hand. The other, a signed holograph which I bought from a bookseller in Texas, has a provenance that is unknown. Swinburne appears to have wanted to publish both, though circumstances in each case made that infeasible..."
Meyers, Terry L., Two Poems by Swinburne: ‘Milton’ and On Wagner’s Music (1993). Victorian Poetry, 31(2), 203-209.
See: Meyers, Terry L. “Erratum: Swinburne on Wagner’s Music: A Misattribution.” Victorian Poetry, vol. 37, no. 4, 1999, pp. 551–551. JSTOR, http://www.jstor.org/stable/40004283.