Beethoven’s Piano Concerto No. 3 was composed in 1803, when Beethoven was 33 years old, and 12 years after Mozart’s death. It falls in the middle of the shifting tectonic plates of Beethoven’s being stuck in the Mozart era and finding his own independent footing as a composer (less “sunshine” Mozart and more darker, moodier Beethoven).
Music critics argue that this concerto was inspired by Mozart’s 24th piano concerto. Though both concertos are focused on the piano, Beethoven’s uses it to a much greater degree, and the piano was going through a major transformation at the time (I wrote about it here).
Beethoven was the piano soloist of the concerto at its premiere. The score for the piano part was not fully finished – Beethoven was playing it from memory. Ignaz von Seyfried, who was lucky to be chosen Beethoven’s page turner for that performance, wrote:
I saw empty pages with here and there what looked like Egyptian hieroglyphs, unintelligible to me, scribbled to serve as clues for him. He played most of his part from memory, since, obviously, he had put so little on paper. So, whenever he reached the end of some invisible passage, he gave me a surreptitious nod and I turned the page. My anxiety not to miss such a nod amused him greatly and the recollection of it at our convivial dinner after the concert sent him into gales of laughter.