Composer Alexander Kastalsky, although he was Rachmaninov‘s teacher, is not well known outside Russia. He wrote mostly church music, and it influenced his famous student and other Russian church composers of the era. This Requiem of 1917 is unique, even within his oeuvre. It’s a grand attempt to write a requiem mass for soldiers of the allied nations of World War I. As such, the mass was an evolving piece of work. At the end of the war, Kataslsky added sections for the United States, Japan, and India, but as Communism took hold, these were barred from performance, and what’s given here, with 17 movements in all, is the world premiere of the full work. One might argue that as pure music, the Requiem isn’t unified in the way that, say, a Beethoven symphony is; it’s not pure music, and there’s something both powerful and consoling about Kataslsky‘s attempt to encompass the scope of the war. The various sections refer musically and textually to Orthodox church music of Russia and Serbia, to the Catholicism of France and Italy, and to the Anglican music of Britain, with the non-Russian traditions just slightly filtered through Kataslsky‘s homegrown lens. The original languages are used, with the result that few hearers would understand the entire text of the work. (Even his Russian pieces are not that intensely Russian, making no use of the deep basses heard in the Rachmaninov Vespers, for instance.) Things get a bit more unusual with the American Movement, which is based on the hymn Rock of Ages (yes, originally British, but recognized as characteristically American even in Russia in 1917), combined with the Chopin Funeral March from the Piano Sonata No. 2 in B flat minor, Op. 35. This is essential listening! Conductor Leonard Slatkin does a superb job holding and melding together a variety of choirs, and leading the Orchestra of St. Luke’s: the performance could easily not have cohered as well as it does. An offbeat work that was well worth retrieving from the scrap heap of history; others will perform it again, but Slatkin has set the bar very high here.