Dance history is tracked with the story of this production. From The Silicon Valley's Mercury News:

"What's most gratifying about "The Toreador" is that the ballet provides a living link to Bournonville's refined, almost reserved style, which itself is a direct link back to the legendary French dancer Auguste Vestris. While dance in Paris evolved rapidly through the 19th century, Copenhagen's isolation meant that the Bournonville style remained largely unchanged. And when Sergei Diaghilev's Ballet Russes swept modernist music and design into European ballet, the Royal Danish Ballet stood outside the powerful current.

"That was a kind of a cocoon for that special French style that was left in Denmark," says Vivi Flindt. "With the Depression and then World War II, we were Isolated, and the whole knowledge of the Danish tradition wasn't discovered until the 1950s. That's why the Bournonville tradition has stayed so intact. No one really knew about it. That's why you can say in Bournonville you have the purist of the French romantic dancing."

 The entire fascinating story is  here.