Dearest friend,
It just occurs to me that in Lohengrin I have forgotten to mark the tempo in one place, which I discovered only when I conducted it here. I mean the Bridal Song in D major, after the second solo passage of the eight women, the last eight bars before the tempo primo.
Here the tempo is to be considerably slower even than at the first entry in D major; the impression must be one of solemn emotion, or else the intention is lost.
Richard Wagner
Source: Project Gutenberg eBook #3835, Correspondence of Wagner and Liszt — Volume 1, No. 133