From the NYTimes

The Catholic delegation, which included Cardinal Francis George of Chicago, was assembled by Cardinal Lustiger, who converted from Judaism as a youngster and speaks Yiddish. Exposing his fellow cardinals to the Yeshiva world, he said, was a way of showing them how to be men of faith in the modern world.

…At a lunch later in the day, Cardinal Lustiger came over to greet Rabbi Steinsaltz, a puckish figure who good-naturedly asked him what Catholic religious authority gave him dispensation from obeying Jewish laws, given that the cardinal remains a Jew in the eyes of Judaism. Cardinal Lustiger answered, none, really, according to the rabbi, though it was not clear how serious the discussion was.