I think it would be Haydn and especially Mozart.
My guess is Haydn and Schubert. (Beethoven was from Bonn in the Rhineland, Mozart was born in independent Salzburg).
These two Austrian composers are considered to be the outstanding examples of late 18th century European music
* Wolfgang Amadeus Mozart * Johann Strauss Jr.
Which composers symphony No7
Beethoven
You have logged this question under 'Mozart', so are you asking for two other Austrian composers whose music is regularly played today? If so, Haydn and Schubert come to mind, but there are others of course.
Franz Joseph Hayden.
Beetoven
batovan, motarts, hyden
Haydn, Mozart, & Beethoven
Someone could find a list of composers for a symphony online on Wikipedia. They could also go to a local library music museum and research there for information.