Task: Question Answering
Input (English): Passage: Lawrence Morton, in a study of the origins of The Rite, records that in 1907–08 Stravinsky set to music two poems from Sergey Gorodetsky's collection Yar. Another poem in the anthology, which Stravinsky did not set but is likely to have read, is "Yarila" which, Morton observes, contains many of the basic elements from which The Rite of Spring developed, including pagan rites, sage elders, and the propitiatory sacrifice of a young maiden: "The likeness is too close to be coincidental". Stravinsky himself gave contradictory accounts of the genesis of The Rite. In a 1920 article he stressed that the musical ideas had come first, that the pagan setting had been suggested by the music rather than the other way round. However, in his 1936 autobiography he described the origin of the work thus: "One day [in 1910], when I was finishing the last pages of L'Oiseau de Feu in St Petersburg, I had a fleeting vision ... I saw in my imagination a solemn pagan rite: sage elders, seated in a circle, watching a young girl dance herself to death. They were sacrificing her to propitiate the god of Spring. Such was the theme of the Sacre du Printemps".By May 1910 Stravinsky was discussing his idea with Nicholas Roerich, the foremost Russian expert on folk art and ancient rituals. Roerich had a reputation as an artist and mystic, and had provided the stage designs for Diaghilev's 1909 production of the Polovtsian Dances. The pair quickly agreed on a working title, "The Great Sacrifice" (Russian: Velikaia zhertva); Diaghilev gave his blessing to the work, although the collaboration was put on hold for a year while Stravinsky was occupied with his second major commission for Diaghilev, the ballet Petrushka.In July 1911 Stravinsky visited Talashkino, near Smolensk, where Roerich was staying with the Princess Maria Tenisheva, a noted patron of the arts and a sponsor of Diaghilev's magazine World of Art. Here, over several days, Stravinsky and Roerich finalised the structure of the ballet. Thomas F. Kelly, in his history of the Rite premiere, suggests that the two-part pagan scenario that emerged was primarily devised by Roerich. Stravinsky later explained to Nikolai Findeyzen, the editor of the Russian Musical Gazette, that the first part of the work would be called "The Kiss of the Earth", and would consist of games and ritual dances interrupted by a procession of sages, culminating in a frenzied dance as the people embraced the spring. Part Two, "The Sacrifice", would have a darker aspect; secret night games of maidens, leading to the choice of one for sacrifice and her eventual dance to the death before the sages. The original working title was changed to "Holy Spring" (Russian:  Vesna sviashchennaia), but the work became generally known by the French translation Le Sacre du printemps, or its English equivalent The Rite of Spring, with the subtitle "Pictures of Pagan Russia". 
Question: What is the full name of the person that worked with Stravinsky on the "The Great Sacrifice?
Output (English): Nicholas Roerich.