'''''Il templario''''' is an Italian-language opera by the German composer Otto Nicolai from a libretto written by Girolamo Maria Marini based on Walter Scott's ''Ivanhoe''.
It has been noted that Nicolai's work for the opera stage, which followed the successful ''Die lustigen Weiber von Windsor'' (''The Merry Wives of Windsor)'' (his only German opera), included three others, all of which were in Italian (two being ''Gilippede ed Odoardo'' and ''Il proscritto'') and all "are all firmly cast in the ''bel canto'' style, with gracefully flowing melodies in the manner of Bellini".Holden, p. 631 Marini was a part-time poet when not employed by the government tobacco monopoly, and is best remembered today for being called in to rewrite the third act of Donizetti's ''Adelia.''.Ashbrook, ''Donizetti'' (Italian edition p. 327)
''Il templario'' received its premiere performances at the Teatro Regio, Turin in 1840, and continued on a successful run through Italy, rivaling Pacini's ''Saffo''. However, it disappeared for over 160 years until it was reconstructed in 2006 and performed in 2008.
The success of Nicolai's opera had an unintended contributing indirect effect on the failure of Verdi's early attempt at the ''opera buffa'' genre, ''Un giorno di regno'', in 1840. The Teatro alla Scala impresario Merelli insisted on using the ''opera seria'' singers previously assembled for Nicolai's opera, which had toured in Milan, thus contributing to the disaster experienced by Verdi.Budden, p.? :"The cast had been assembled chiefly for the performance of the season's most successful novelty, ''II templario'', Nicolai's version of ''Ivanhoe''".