Complex sentence: In 1957 he was granted the use of Central Park for free productions of Shakespeare's plays, which have continued through 2009 at the open-air Delacorte Theatre.
Split into simpler sentences: In 1957 he was granted the use of Central Park for free productions of Shakespeare's plays. This legacy of Papp's has continued (through 2009) at the open-air Delacorte Theatre.