It has been a long time time since I studied French in school, but I am fairly sure I learned that ordinal numbers are spelled with an accent grave (deuxième, troisième, etc.), and a cursory online search seems to confirm this. However, I was recently looking at some printed French sheet music from the 18th century (François Couperin's Les goûts-réunis, available in PDF form at IMSLP) in which the titles of successive pieces are apparently spelled with an accent aigu: Cinquiéme concert, Sixiéme concert, etc.:
Has the accepted spelling of ordinal numbers changed since this music was printed in 1724? Or is this somehow an artifact of the kind of calligraphy used for the titles?