Conversation so far:
What is important about this period of time for Schumann?
By Christmas he was back in Leipzig, at age 20 taking piano lessons from his old master Friedrich Wieck, who assured him that he would be a successful concert pianist.
Did he perform any concerts during this period?
Schumann abandoned the idea of a concert career and devoted himself instead to composition.

Question: Why did he abandon the idea of a concert career?
Self-contained rewrite: Why did Schumann abandon the idea of a concert career?