There is an earlier-published (1880s) Tantum ergo by "J. Faure" (the same?) in major (E♭ in the version there) (arranged for 3 voices but perhaps also originally for solo voice and organ) that's entirely different melodically etc. How to distinguish the two? "Tantum ergo No.1 (Faure, Jean-Baptiste)" doesn't seem quite right as actually there's no knowing (without checking RISM, anyway, and even that doesn't give a certainty usually) how many he wrote and what order they were in. (Also, Faure really should be Fauré in both cases shouldn't it?- I can't imagine the composer's name being pronounced "Four"?") Naming the new workpage Tantum ergo in E-flat major doesn't really work since the key is contingent on the voice type there as here... Eric 17:55, 15 February 2012 (UTC)
Note: the one at LoC is a 3-voice arrangement of Eric 17:57, 15 February 2012 (UTC) (See here at LoC. RISM claims that it is also an Ave Verum, which may solve the placement problem quite nicely- I'll go recheck when I get back in an hour or so and create a page for it sometime today perhaps under Ave verum (Faure etc. if so ... )whose autograph is dated 1869/1870.