I briefly confused the two pieces earlier today when the ending of the 1812 Overture, starting at this point finale was used as background music in a youtube video. I've played Pictures at the Exhibition many times in orchestra before (both the Ravel and Stokowski versions) but have barely listened to the 1812 Overture, and the similarity to the opening of the Great Gate of Kiev here took me by surprise. I've been trying to uncover a link between them all evening: as both composers knew each other and I thought one might be a direct reference to the other, or that they both had a common inspiration.
Bars 358-379 of the 1812 Overture references the Russian Orthodox hymn "Lord, preserve thy people", the first three chords of which are quite similar to the opening ones of "The Great Gate of Kiev". When trying to find the basis for the latter, several sources on Mussorgsky all say that it is a different Russian Orthodox hymn called "As you Are Baptized in Christ" (Bricard, Nice, Russ, Houston Symphony, Quick).
I'm trying to find this melody so I can compare it to the opening of "Lord, preserve they people". However, every search for "As you Are Baptized in Christ" only leads back to texts about Mussorgsky - it doesn't seem to exist in any other context. I've unsuccessfully tried using Google Translate to generate other plausible translations of the name of the hymn. I haven't found anything that looks right on Youtube either when searching in Russian using translations of the hymn name.
Does any suggestions of how to find "As You Are Baptized in Christ"? I've had a look through an English-Russian hymnbook but the name didn't come up. I'm not particularly familiar with either Russian Orthodox music, or other Christian music traditions, so I may be missing something quite straightforward.