R. Oldenbourg München-Berlin
Verlag Der Corona Zürich
Copyright 1937

Translated excerpt (page 20):

     This summer I solemnly declared to Rilke, with great pleasure, that I wanted to find a special name for him, only for me. I found "Rainer Maria Rilke" too long, "Rilke" too short, and "Rainer Maria" lacking enough dignity to be his true name. How he laughed over this explanation, over my respect, and my difficulties! But the name I would contrive for him came to me very curiously.
     "A new name! Do you think, Princess, that something terrible might happen- that perhaps it will be my actual name, a mysterious name that belongs to me..." Doctor Seraphicus! [Dottor Serafico.] It occurred to me very suddenly as if it was murmured to me from some unknown place; I repeated it over and over, wondering whether this unexpected name was the correct name for him. And yes... what strange ominous Inspiration! I understood it deeply in my heart when that hour finally came, the hour of his second Elegie, that wonderful Elegie of the Angels!
     On the 23rd of July, Serafico, as I called Rilke henceforth, arrived in Lautschin [Princess Marie's estate in Bohemia]. It was a lovely summer...