It was common in opera composition to save the Overture for last. Beethoven had not quite finished the new Overture for Fidelio in time for the first performance on 23 May 1814, so another was substituted. The new Overture was first heard in the second performance on 26 May.
#Beethoven250 Day 267
Fidelio Overture (Opus 72), 1814
The Fidelio Overture is often played by orchestras independently of the opera, as in this socially distanced performance by the Frankfurt Radio Symphony.