“A greatly talented choreographer is taking risks,” wrote the dance critic Arlene Croce of Kenneth MacMillan and his Mayerling, created for the Royal Ballet in 1978. This three-act study of royal privilege and pathology—with not two or three pas de deux but seven (!)—tells the story of Crown Prince Rudolf of Austria-Hungary, who ended it all in a hunting lodge, in a suicide pact with his mistress Mary Vetsera. The sumptuous sets and costumes are by MacMillan’s frequent collaborator, the Greek painter and designer Nicholas Georgiadis. Like Antony Tudor, MacMillan took on subject matter that no one guessed they’d ever see at the ballet. “I wanted dance to express something largely outside its experience,” MacMillan explained. “I had to find a way to stretch the language—otherwise I should just produce sterile academic dance.” Sterile his work is not. These are challenging roles, full of passion. —Laura Jacobs