The “Messiah” was performed more than fifty times in Handel’s lifetime. Most of  these performances took place in theatres or secular buildings, as did the first performance on 13th April 1742 in Dublin. In 1750, i. e. nine years later, the composer himself conducted the first church performance in the chapel of the Foundling Hospital, London. Thr differences in acoustics and size between a church and a theatre or concert hall explain the pronounced disparities in the size of orchestra and chorus on various occassions. In the first performance in Dublin the chorus consisted of eight singers for each voice, making 32 in all. Traditionally the orchestra was of a size roughly equal to that of the choir, i. e. six to eight first violins, as many seconds, four or five violas, two cellos, two double basses and the requisite continuo instruments (harpsichord, organ); two trumpets and timpani. Although oboes and bassoons are not specifically listed in the score, Handel would, in accordance with the prevailing custom, have used them as a matter of course in all appropriate places to impart colour, outline and power to the tutti; indeed, this is confirmed by extant copies of the Foundling Hospital performance. Incidentally, the scoring on that occasion was relatively generous - 33 instrumentalists.
Thus the score, the musical substance, is not affected within fairly wide limits by the size of the orchestra; the acoustics of the hall are of far greater significance. (Other scores of that period, for example Bach`s cantatas and oratorios, are nowhere near as adaptable: here the size of chorus and orchestra is determined much more critically by the need to maintain a balance between the instruments.) - Soon after Handel’s death his oratorios were performed with colossal forces. In Westminster Abbey, in 1784, there was a chorus of 300 with 250 instrumcntalists: 95 violins, 26 violas, 21 cellos, 15 double basses; 26 oboes, 28 bassoons, 12 horns, 12 trumpets, 6 trombones. Of course the solo parts were taken by more than one performer; one wonders what the horns and trombones played. In Berlin, in 1781: 185 instrumentalists. In Leipzig in 1781: 90 choristers, 127 instrunientalists. No doubt the echo in the churches and the enormous number of participants affected the tempi, but one can well imagine that the essence of Handel`s work was not thereby impaired.
Handel wrote his “Messiah“ in barely 21 days. He must thus have composed the work in one tremendous burst between 22nd August and 12th September (his autograph score contains the remarks angefangen [commenced] den 22 August 1741 and Fine dell'Oratorio. G. F. Handel September 12). The orchestration was completed two days later: “ausgefüllet [scored] den 14 dieses [inst.] 1741."
The impact that “The Messiah" made on the audience must from the outset have been tremendous and shattering - “the finest Composition of Musick that ever was heard...“ according to a contemporary report, although the more than self-confident librettist Charles Jennings as ever found something to criticise: “I gave Handel... Messiah, which I value highly, and he has made a fine Entertainment of it, tho’ not near so good as he might and ought to have done. I haye with great difficulty made him correct some of the grossest faults in thc composition, but he retained his overture obstinately in which there are some passages far unworthy of Handel but much more unworthy of the Messiah.“ When Lord Kinnoul congratulated Handel on his splendid "entertainment", he is reported to have replied: “I should be sorry if I only entertained them; I wished to make them better." Because of the varying; conditions for the many repeat performances in different places Handel had to make many changes; consequently it is extremely difficult today to find a version which one can describe as authentic and definitive.

I have tried to discover the reasons for every one of the different versions in order to determine what was the product of expediency occasioned by the specific conditions of a particular performance and what represented new development. When making these comparisons, I was especially struck by the fact that none of these alterations affected the architecture of the work as a whole. I gained an increasing insight into this musico-dramatic architecture until eventually I became convinced that the oratorio must on no account be shortened unless one is prepared to accept substantial damage to the logic of the work. After all, at the end of the 18th and in the 19th century this work, in particular, was merely thought of as a number of individual pieces strung together. Thus Goethe replied to Zelter, who had performed it in Berlin: “I am not disinclined to accept the idea that it is a collection, a compilation from a rich source of supply; since fundamentally it does not matter in the least whether the unity is formed at the beginning or the end; it is always the spirit that produces it in either case and here the unity was implicit in the Christian purpose of the work from the very outset."
The very choice of material, fitting no liturgical form and combining passages from the Old and New Testament with original texts, distinguishes the “Messiah“ from comparable oratorios. In his setting Handel has reinforced internal correlations by interlinked motifs, the relationship of keys and the arrangement of solo and choral passages.
The oratorio is divided into three clearly distinct parts:
(1) The prophecy of the Messiah and the birth and life of Jesus, the Messiah;
(2) The achievement of salvation through the suffering of Jesus; his rejection by man - the victory of the Messiah;
(3) A hymn of thanks for the conquest of death.
The present recording was taped live in the course of two performances in Stockholm on 8th and 9th November 1982, in which an attempt was made to present the oratorio and to make it intelligible as a clearly structured unity.
(...)