Beethoven’s piano concerti, which build on what Mozart had been writing for his own self-publicising concerts, including increasing solo woodwind writing, are numbered in publishing order, not date written.
Numbering is a funny thing – Bruckner wrote a symphony in between composing what we now know as 1 and 2, but he later declared ‘it does not exist’, so it’s known as Bruckner 0.
The Listening Project Blog 