Grafted into What? Romans 11 and our Identity As Christians

Were Gentiles grafted into Israel? Israel into the church? The church into Israel? Or Israelites and Gentiles into the church?

Rom. 11 http://bible.fether.net/index.php?book=6&chap=11&pager=en
commentary on Romans http://bible.fether.net/index.php?book=6&pager=co