Given the question: What rank was the composer who composed a piece for the Paris Opera in the 1970s promoted to in 1987?  Answer the above question based on the context below:  Messiaen's next work was the large-scale La Transfiguration de Notre Seigneur Jésus-Christ. The composition occupied him from 1965 to 1969 and the musicians employed include a 100-voice ten-part choir, seven solo instruments and large orchestra. Its fourteen movements are a meditation on the story of Christ's Transfiguration. Shortly after its completion, Messiaen received a commission from Alice Tully for a work to celebrate the U.S. bicentennial.  He arranged a visit to the US in spring 1972, and was inspired by Bryce Canyon in Utah, where he observed the canyon's distinctive colours and birdsong. The twelve-movement orchestral piece Des canyons aux étoiles... was the result, first performed in 1974 in New York.In 1971, he was asked to compose a piece for the Paris Opéra. While reluctant to undertake such a major project, he was persuaded in 1975 to accept the commission and began work on his Saint-François d'Assise. The composition was intensive (he also wrote his own libretto) and occupied him from 1975 to 1979; the orchestration was carried out from 1979 until 1983. Messiaen preferred to describe the final work as a "spectacle" rather than an opera. It was first performed in 1983. Some commentators at the time thought that the opera would be his valediction (at times Messiaen himself believed so), but he continued to compose. In 1984 he published a major collection of organ pieces, Livre du Saint Sacrement; other works include birdsong pieces for solo piano, and works for piano with orchestra.In the summer of 1978, Messiaen retired from teaching at the Conservatoire. He was promoted to the highest rank of the Légion d'honneur, the Grand-Croix, in 1987. An operation prevented his participation in the celebration of his 70th birthday in 1978, but in 1988 tributes for Messiaen's 80th included a complete performance in London's Royal Festival Hall of St. François, which the composer attended, and Erato's publication of a seventeen-CD collection of Messiaen's music including a disc of the composer in...
The answer is:
Grand-Croix