Could Sauron "corrupt" the Blessed Realm?
This version of "The Council of Elrond" appears in "The History of Middle-earth" and discusses the dangers of Sauron obtaining the three Elven rings:
>Now is the time for true speaking. Tell me, Elrond, if the Three Rings still are? And tell me, Gloin, if you know it, whether any of the Seven remain?'
>'Yes, the Three still are,' said Elrond, 'and it would be ill indeed if Sauron should discover where they be, or have power over their rulers; for then perhaps his shadow would stretch even to the Blessed Realm.'
But how is that possible? During the Third Age, the Blessed Realm was not even in Arda.