how many parts does it have?
3 parts
Introduction
The text begins in Part I with prophecies by Isaiah and others, and moves to the annunciation to the shepherds, the only "scene" taken from the Gospels. In Part II, Handel concentrates on the Passion and ends with the "Hallelujah" chorus. In Part III he covers the resurrection of the dead and Christ's glorification in heaven.
who wrote the hallelujah chorus from handel messiah George Frideric Handel what is it? It is an English-language oratorio, with a scriptural text compiled by Charles Jennens from the King James Bible, and from the Coverdale Psalter, the version of the "Psalms" included with the "Book of Common Prayer". when was it composed? 1741
Three Part I, Part II, Part III Three
Messiah (Handel) Messiah (Handel) Messiah (Handel)
Part I Introduction Synopsis
The opening "Sinfony" is composed in E minor for strings, and is Handel's first use in oratorio of the French overture form. Jennens commented that the "Sinfony" contains "passages far unworthy of Handel, but much more unworthy of the Messiah"; Handel's early biographer Charles Burney merely found it "dry and uninteresting". A change of key to E major leads to the first prophecy, delivered by the tenor whose vocal line in the opening recitative "Comfort ye" is entirely independent of the strings accompaniment. The music proceeds through various key changes as the prophecies unfold, culminating in the G major chorus "For unto us a child is born", in which the choral exclamations (which include an ascending fourth in "the Mighty God") are imposed on material drawn from Handel's Italian cantata "Nò, di voi non-vo'fidarmi". Such passages, says the music historian Donald Jay Grout, "reveal Handel the dramatist, the unerring master of dramatic effect".

The pastoral interlude that follows be The text begins in Part I with prophecies by Isaiah and others, and moves to the annunciation to the shepherds, the only "scene" taken from the Gospels. In Part II, Handel concentrates on the Passion and ends with the "Hallelujah" chorus. In Part III he covers the resurrection of the dead and Christ's glorification in heaven. The three-part structure of the work approximates to that of Handel's three-act operas, with the "parts" subdivided by Jennens into "scenes". 
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Messiah (Handel) [SEP] Introduction
In Part III he covers the resurrection of the dead and Christ's glorification in heaven. Handel wrote "Messiah" for modest vocal and instrumental forces, with optional settings for many of the individual numbers. In the years after his death, the work was adapted for performance on a much larger scale, with giant orchestras and choirs. In other efforts to update it, its orchestration was revised and amplified by (among others) Mozart ("Der Messias"). In the late 20th and early 21st centuries the trend has been towards reproducing a greater fidelity to Handel's original intentions, although "big "Messiah"" productions continue to be mounted.