Handel's Messiah includes some twenty choral numbers, fifteen recitatives and arias for soloists, two orchestral pieces and two vocal duets, all of which amount to about two and a half hours of music. Far from discouraging music lovers, this great musical fresco centred on the Christ already established itself during Handel's lifetime as one of the most popular choral works ever composed.
The libretto was drafted out in 1741, at a time when the London audience had turned its attention from Italian opera to epic Biblical stories. Handel was obliged to adapt to the local taste and therefore began once again to compose oratorios, a genre he had already approached in his younger years. Inspired by his former opera experience, the composer enhanced the model provided by the Italian oratorio with numerous choruses and a true dramatic dimension, thus creating from scratch the "English oratorio". Such productions enabled Handel to satisfy both the expectations of the moralistic Protestant middle class and his own desire to impress with grandiose compositions.
Although Handel's Messiah is by far his most famous choral work, it paradoxically occupies a marginal place in the composer's production, since it is one of the few Handelian oratorios based on Biblical texts. The "libretto" was prepared by Charles Jennens, a wealthy gentleman and patron of the Arts who had already conceived the librettos of several Handel oratorios, including Saul and Israel in Egypt. For Messiah, Jennens gathered passages from the Old and New Testaments, which refer to the Resurrection of the Messiah and Christian redemption. There is little direct narration: the work is far more the musical setting of a long sermon addressed to a mid-18th-century British audience for whom the reading of the Bible was common practice.
Handel composed his Messiah at the end of the summer of 1741, within three weeks. The first performance took place the following spring in Dublin, one of the most active musical and literary centres in the 18th century. The success of this Irish premiere was not immediately repeated in London since devotees decided to contest Handel's oratorio: they considered the work's title far too sacred for a theatre performance of Messiah. However, the situation improved from 1750 onwards, when Handel became accustomed to conducting his oratorio in the chapel of one of the charitable foundations appreciated by the London high society. From then on, Messiah enjoyed an increasing success that kept pace with the rising number of performers on stage. Handel subsequently reworked the score on several occasions, according to the number of musicians and singers available.