Perhaps I can restart a new thread on the Requiem attributed to Zelenka (ZWV 45). I recently started to become interested in this work. I noticed that it was discussed on this site 10 years ago in a thread with a different title (see here). At the time, various members of this forum gave their opinion, some seeming to support the notion that some or all of ZWV 45 could be from the quill of Zelenka, others less convinced. I wondered what is the current status on this issue - have there been any new academic developments which help assign this work?
I admit I totally dismissed ZWV 45 the first time I heard it - I listened to the old Dähler version. It is so dreamily (and sometimes drearily) performed I just could not reconcile it with the tension and/or energetic devotion of most of Zelenka's output. More recently, a rekindled fascination with ZWV 57 led me to acquire the Fiori Musicali album (I know, the version of ZWV 57 there is not the best). ZWV 45 is on that disk too and listening to it was quite a revelation. Time and again I suddenly found myself being sort of comfortable with Zelenka having written this. That is partly because bits of it are so weird and also there is such a juxtaposition of "ancient and modern" styles I am not sure that there are many composers who it could be fairly attributed to - they were all so normal baroque composers! However, there are still enough un-zelenka traits which bring doubts. The unusual scoring (no oboes) was brought up in the earlier thread. And then there are the slightly frivolous settings of some parts of the Sequenzia (esp. the lethally catchy "Tuba mirum"). That view might be the fault of the performance, however. It would be great to hear what the two current best Zelenka interpreters (Viktora or Luks) might make of those sections. I bet that they could make them sound more Zelenkan and also more appropriate for a requiem. Another concern is the frequent use in ZWV 45 of the tierce de picardy. Maybe I am wrong but I don't think Zelenka uses that device much or even at all. So, overall I could accept that Zelenka composed this work, but probably in a scenario where it was for a very unique occasion where it demanded some differences from his "usual" works (if such a thing existed for him!). I guess one theory, mentioned by djdresden in the old post is that ZWV 45 is the requiem written for Zelenka's dad. Perhaps daddy was a fan of the tierce de picardy or might have been so devout that it was ok for his trumpet of judgement to be jolly merry. The music certainly contains moments of intense emotion which could be consistent with a very personal loss of its composer. Moreover, it would have been improper for Zelenka to demand the royal musicians put on a grand affair for a commoner. Hence the sparse scoring (strings and poignant trombones).
I would like to throw another theory into the ring that I did not read in the old thread and also nowhere else (but could well have been proposed elsewhere already). How about Heinichen as the composer of part or all of ZWV 45? I listened to quite a lot of Heinichen lately and his vocal music often has almost as much quirkiness and invention as Zelenka's. Moreover, depending on the interpretation, some Heinichen works could easily be mistaken for Zelenka's. There is a recording of Heinichen's Requiem in E flat (Seibel 18) on YouTube - https://www.youtube.com/watch?v=C646YhKes8g . I encourage you to listen to that in alternation with ZWV 45. While the scoring is richer (oboes, flutes etc), I can't help but notice some similarities. Like ZWV 45, the work is quite reflective and Heinichen also merges ancient and modern. There are also some quirky tunes (like the gently burbling and not at all wrathful Dies Irae). Heinichen's fugues are often a bit less complex (and shorter) than Zelenka's and this also seems to fit with ZWV 45. So, all in all, I reckon he could also be a reasonable candidate. Any comments of opposition or agreement?