Filled with love so true, True to a delicious dream…
It's the poem that was so important in The Idiot, the one Aglaya recited somewhere in Part 2 after Myshkin recovered from his seizure to say that Myshkin is in love with Nastasya. Stepan Trofimovich seems to think that he's the poor knight - he isn't, though he may venture to be now.
Stepan had