Complex sentence: The opera was premiered on a small lake outside Toronto in 1981 by New Music Concerts and again in 1985 for the Banff School of Fine Arts summer festival on a more remote lake in Banff National Park.
Split into simpler sentences: The opera was premiered on a small lake outside Toronto in 1981 by New Music Concerts. Then again in 1985 for the Banff School of Fine Arts summer festival on a more remote lake in Banff National Park.