I want to know the answer to the following question:
What historian commented that the events involving Frédéric's friend in Poland contributed to his maturing?
All the background I'm provided with is that "Chopin's successes as a composer and performer opened the door to western Europe for him, and on 2 November 1830, he set out, in the words of Zdzisław Jachimecki, "into the wide world, with no very clearly defined aim, forever."". Is that enough to answer the question?