Pennsylvania Ballet gave an encore of a signature work and added another Balanchine ballet to its repertoire for its opening Thursday night at the Academy of Music. Both were part of the company's yearlong 50th anniversary celebration.

Carmina Burana has been in the troupe's repertoire since 1966, when John Butler staged his 1959 work on Pennsylvania Ballet to Carl Orff's secular cantata. In 2007, choreographer-in-residence Matthew Neenan reinterpreted the ballet with new choreography, costumes, and sets.

For the anniversary, artistic director Roy Kaiser chose to acknowledge the Butler version's place in Pennsylvania Ballet history, but the company says Neenan's will be back after this season. Dueling Carminas? That's unusual, but both are worthy.

Carmina Burana is a feast of music and dance, with vocals by the Philadelphia Singers and ChildrenSong of New Jersey, and solo singers performing on stage alongside the dancers. It is the story of traveling minstrels who abandon their religious customs to enjoy all that life has to offer.

The Butler version is a looser telling of the story but no less beautiful, opening and closing with a dramatic scene of caped dancers kneeling and bowing to the booming music.

It highlights just four dancers: Alexandra Hughes, a corps de ballet member lately featured in several principal roles; soloist James Ihde; and principal dancers Brooke Moore and Ian Hussey. All are excellent, but Moore owns the stage.

The corps gets some of the best partnering work, with the women wrapped around the men's bodies or lifted in unusual, occasionally awkward positions.

The evening opened with Stravinsky Violin Concerto, a black-and-white Balanchine leotard ballet that was a company premiere. As with most Balanchine ballets, the company - started by his protégée Barbara Weisberger - rose to the occasion.

Amy Aldridge and Jong Suk Park were the unannounced replacements for Julie Diana and the injured Zachary Hench, and were both excellent. Aldridge dances with such expression and personality that she seems to add a plot to the plotless ballet.

Jermel Johnson has been a favorite since joining the company, with his exuberance and stunning jumps. He has matured as an artist, but was no less magnetic in his role.

Lauren Fadeley particularly impressed in a fast section, expressing every musical nuance with a different step.

The program is slightly heavy. A third, lighter ballet would have provided better balance. But if you enjoyed the Butler Carmina over the years and thought you might never see it again, now is your chance.