Italian to English Art/Literary Music

First performance ever? The phrase comes from a pamphlet I'm translating for the 69th Biennale at Venice - music section. It gives the name of a composer, the title of an opera or other musical composition, it's duration, and then often has this abbreviation above (prima es. ass.), and sometimes "prima es. it.", which I supposed to mean 'first time played in Italy".

Is there a precise way of expressing this concept? First ever performance?

Thanks,

Peter