Fr. Hans Urs von Balthasar, one of the most celebrated theologians of Progressivism, was considered the mentor of John Paul II.
In November 1985 he granted an interview to 30 Giorni magazine about Vatican II. The reporter who conducted that interview was Angelo Scola, today Cardinal Archbishop of Venice.
In one of the questions, Scola insinuated that Ratzinger had changed his views from a progressivist theologian to a conservative Prefect of the Congregation for the Doctrine of the Faith.
Even before Scola had finished formulating his question, Von Balthasar jumped "to the defense" of Ratzinger affirming that he had never changed his convictions.
This is certainly an authoritative testimony...
At right top is page one of the interview with a close-up of von Balthasar being interviwed by Scola. At right, photocopies of the Italian text. Below, we present our translation of the lines highlighted in yellow.
... Ratzinger has always been for an advanced position and openness.
I have known him for a long time, since he was a professor, and I can assure you that he did not change.
Everyone says the opposite, that there are two Ratzingers: one before he came to Rome, and a different one later.
To the contrary, he has always remained the same!
(Hans Urs von Balthasar, "Viaggio nel Postconcilio", interview with Angelo Scola, 30 Giorni, November 1985, p. 16.