Conversation so far:
what happened in 2006?
Studdard's third album, The Return was released in October 2006.
how did the album do?
The Return sold 71,000 copies in its first week to open at number eight on the Billboard 200 album chart, but sales declined rapidly after that.
why did sales decline rapidly?
it goes back to his R&B roots, but is different from his previous efforts.

Question: what was his greatest accomplishment?
Self-contained rewrite: what was Ruben Studdard's greatest accomplishment?