Jennens was brought up at Gopsall Hall in Leicestershire, the son of Charles Jennens and his second wife, Elizabeth Burdett. He was educated at Balliol College, Oxford, matriculating in 1716, but did not graduate. A devout Christian and a non-juror, upholding the legitimacy of the deposed Stuart line. He became interested in "primitive Christianity" and John Chrysostom. Jennens has been identified as an anti-Deist. Richard Kidder's book A Demonstration of the Messias influenced him.
After his father's death in 1747, Jennens had Gopsall Hall completely rebuilt in the Palladian style, including within the estate an Ionic temple built in memory of his friend, the poet and classical scholar, Edward Holdsworth. Remaining unmarried, he was considered melancholic and extravagant, his neighbours calling him Suleyman the Magnificent. As a non-juror, Jennens was ineligible for any public appointment, and he devoted himself to the arts, both as a collector of fine art (his collection was one of the best in Britain at the time) and a music patron. George Friderick Handel's compositions were very much to his musical taste and they became close friends. Handel visited him frequently at Gopsall Hall and in 1749 provided the specification for an organ for his home. Thomas Hudson's portrait of Handel was commissioned by Jennens – and the same artist's portrait of Charles Jennens is now in the Handel House Museum in London.
After his death, Jennens' second cousin Heneage Finch, 3rd Earl of Aylesford, inherited his music library and much of it is now preserved in the Henry Watson Music Library at Manchester Central Library. It contains a large collection of manuscripts and published music by Handel and other contemporary composers, both English and Italian; there are 368 volumes of Handel manuscripts, and others include the autograph of Vivaldi's "Manchester" violin sonatas and an early manuscript of "The Four Seasons". Jennens' extensive collection of books by Shakespeare, on literature, philology and theology was largely dispersed in a sale in 1918.
Collaboration with Handel
Jennens' deep knowledge of the Bible and wide literary interest led him, from 1735, to prepare or contribute to libretti for Handel. These included Saul (1735–39), L'Allegro, il Penseroso ed il Moderato (1740–41), Messiah (1741–42), Belshazzar (1744–45) and, possibly, Israel in Egypt (1738–39). The libretti were freely given and always published anonymously. Saul and Belshazzar are said to "show an impressive gift for dramatic structure and characterization and the ability to wield political analogies adroitly."
Well versed in music as well as literature, he annotated his copies of Handel's operas, adding corrections, bass figures, rejected pieces and dates. It is also clear that on occasions Handel was prepared to accept Jennens' suggestions and improvements to his compositions.
The most famous collaboration is Jennens' libretto for Messiah, drawn entirely from the Bible, about 60% from the Old Testament (with occasional small alterations). Musicologist Watkins Shaw describes it as "a meditation of our Lord as Messiah in Christian thought and belief", and which "amounts to little short of a work of genius". Some attribute Messiah's emphasis on the Old Testament – and choice of the Old Testament title "Messiah" – to Jennens' theological beliefs. Jennens was less than wholly approving of the musical setting, writing to Edward Holdsworth:
"I shall show you a collection I gave Handel, called Messiah, which I value highly. He has made a fine entertainment of it, though not near so good as he might and ought to have done. I have with great difficulty made him correct some of the grossest faults in the composition; but he retained his overture obstinately, in which there are some passages far unworthy of Handel, but much more unworthy of the Messiah."
Editor of Shakespeare
In the early 1770s Jennens commenced the preparation of scrupulous critical editions of Shakespeare plays, and the first time that these had been published individually and with editorial footnotes. He completed King Lear, Hamlet, Othello, Macbeth, and Julius Caesar before his death in 1773. These editions drew scorn, perhaps due to envy, from the Shakespeare editor George Steevens who severely attacked not only Jennens' work, but particularly his character: "The chief error of Mr. Jennens's life consisted in his perpetual association with a set of men every way inferior to himself. By these means he lost all opportunities of improvement, but gained what he preferred to the highest gratifications of wisdom – flattery in excess."
- "Mr. Charles Jennens: The Compiler of Handel's 'Messiah'". The Musical Times and Singing Class Circular. 43 (717): 726–727. 1 November 1902. doi:10.2307/3369540. JSTOR 3369540.
- Smith, Ruth. "Jennens, Charles (1700/01–1773)". Oxford Dictionary of National Biography. Oxford University Press. Retrieved 15 February 2013.
- Daniel, David (2003). The Bible in English. Washington DC, US: Library of Congress. p. 563. ISBN 0-300-09930-4. Retrieved 27 January 2013.
There can be no doubt that Jennens saw his compilation of Scripture texts as forcefully attacking deism. The very title is an anti-deist banner.
- Handel. A Celebration of his Life and Times 1685–1759, p. 201. National Portrait Gallery London
- Gudger, William D. "George Frideric Handel's 1749 Letter to Charles Jennens" (PDF). The Moldenhauer Archives. Library of Congress, Washington DC. Retrieved 15 February 2013.
The organ survives, substantially unaltered in St James' Church, Great Packington, Warwickshire
- "Portrait of Charles Jennens". The Art Fund. Retrieved 15 February 2013.
- "Henry Watson Music Library: Manuscripts and Rarities". Manchester City Council. Archived from the original on 30 August 2011. Retrieved 15 February 2013.
- Tassilo Erhardt, Händels Messiah. Text, Musik, Theologie, Comes Verlag, Bad Reichenhall 2007, ISBN 978-3-88820-500-2
- Dean, Winton (2006). Handel's Operas. Woodbridge UK: Boydell Press. pp. 122, 278, 302, 310. ISBN 1-84383-268-2.
- Block, Daniel I. (Spring 2001). "Handel's Messiah: Biblical and Theological Perspectives". Didaskalia. 12 (2): 1–23.
- Shaw, Watkins (1963). The story of Handel's "Messiah". London: Novello & Co.
- Bartlett, Clifford (1998). George Frideric Handel: "Messiah" (vocal score). Oxford University Press. ISBN 978-0-19-336668-8.
- Tobin, John (1969). Handel's Messiah. London: Cassell & Co. pp. 150–151. ISBN 978-0-304-93163-7.
- Nichols, John (1812). Literary Anecdotes of the XVIII Century. 3. London. pp. 121–24n.
- Smith, Ruth (2012). Charles Jennens: The Man Behind Handel's Messiah. London: The Gerald Coke Handel Foundation. ISBN 978-0-9560998-2-2.
- Amanda Babington and Ilias Chrissochoidis, "Musical References in the Jennens–Holdsworth Correspondence (1729–46)," Royal Musical Association Research Chronicle 45:1 (2014), 76–129.