Prince Ioann Konstantinovitch (1886-1918) - letters

[Marc]

Does anybody know, who had precedence in Imperial court?

Did Princess Elena had precedence over all Princes/Princesses of blood(styled as HH) as the only member of the Imperial family who was still HRH after her marriage or was she treated as wife of HH? 

[Marc]

I started reading this book about Princess Helena Petrovna:

https://www.livelib.ru/book/1002711921-krasnye-maki-dlya-knyagini-galina-shevtsova?es=881807

Regarding my own question, I found out that in Imperial protocol Princess Helena had higher place in hierarchy than her husband Ioann. As HRH and daughter of the reigning King, she was placed higher and had "the right" to formally receive diplomats, while her husband, based on his title and place in Imperial family(being downgraded from HIH Grand Duke to HH Prince of Imperial blood) did not have this right, as he kept being "only" HH.