Prince Johann Ernst of Saxe-Weimar
|Prince Johann Ernst|
|The Red Castle in Weimar where Johann Ernst lived with his brother Duke Ernst August I|
|House||House of Wettin|
|Father||Johann Ernst III, Duke of Saxe-Weimar|
|Mother||Charlotte Dorothea Sophia of Hesse-Homburg|
25 December 1696|
|Died||1 August 1715
Johann Ernst of Saxe-Weimar (German: Johann Ernst von Sachsen-Weimar) (25 December 1696 – 1 August 1715) was a German prince, son by his second marriage of Johann Ernst III, Duke of Saxe-Weimar. Despite his early death he is remembered as a collector and commissioner of music and as a composer some of whose concertos were arranged for harpsichord or organ by Johann Sebastian Bach, who was court organist in Weimar at the time.
Johann Ernst was born in Weimar, the fourth son and sixth child of Johann Ernst III, Duke of Saxe-Weimar, and second child of the Duke's second wife, Charlotte Dorothea Sophia of Hesse-Homburg. As a young child the prince took violin lessons from G.C. Eilenstein who was a court musician.
He studied at the University of Utrecht between February 1711 and July 1713. It is thought that Johann Ernst furthered his understanding of music at this time. From Utrecht, he could visit such centres as Amsterdam and Düsseldorf and it is known that he had copies of Italian music sent back to Weimar. (Household bills for the year from 1 June following his return record the cost of copying, binding and shelving music.) In particular, it is thought that he might have encountered Vivaldi's opus 3 set of violin concertos. The prince's interest in collecting music was sufficiently well known that P. D. Kräuter, when requesting leave of absence to study with Bach in Weimar, mentioned the French and Italian music that the prince was expected to introduce there. Kräuter also praised Johann Ernst's virtuosity as a violinist.
On his return from university, Johann Ernst took lessons in composition with a focus on concertos from the local church organist Johann Gottfried Walther, a cousin of Bach. Walther had previously given the prince keyboard lessons and had given him his Praecepta der musikalischen Composition (Precepts of Musical Composition) as a twelfth birthday present.
During his life, Walther transcribed seventy-eight concertos for keyboard. Bach also produced a number of virtuoso organ (BWV 592–6) and harpsichord (BWV 972–987) arrangements. These included some of the prince's own works (BWV 592, 592a, 982, 984 and 987) as well as works by German and Italian composers, including Georg Philipp Telemann (BWV 985) and Vivaldi (BWV 972, 973 etc.). The Bach transcriptions were created roughly during the period July 1713–July 1714 between Johann Ernst's return from Utrecht and the prince's final departure from Weimar. There is some scholarly debate on Johann Ernst's role in the creation of these arrangements, whether he commissioned some from one or both of the musicians or whether Bach, in particular, was studying some of the works collected by the prince for their own sake. There are suggestions that on a visit to Amsterdam in February 1713 the Prince may have heard the blind organist J. J. de Graff, who is known to have played keyboard arrangements of other composers' concertos. In any case, Bach's encounter with the prince's collection, and especially the Italian music it contained, had a profound influence on the development of the composer's musical style. 
As well as influencing Bach, Johann Ernst completed at least nineteen instrumental works of his own before his death at age eighteen. These works show the influence of Italian music more than that of German models such as Bach.
Johann Ernst died in Frankfurt after a long illness resulting from a leg infection, and was buried, not in Weimar, but in Homburg (Bad Homburg vor der Höhe) in the vault of his mother's family, the Landgraves of Hesse-Homburg. A period of mourning was declared in Weimar from 11 August to 9 November 1715. Music was banned, including in church, resulting in an interruption in Bach's attempt to build an annual cycle of cantatas.
Following his death, six of the prince's concertos were sent to Telemann, who edited and published them in 1718. He himself had already started to have them set before his death. Telemann's own first publication, a 1715 set of six violin sonatas, had been dedicated to Johann Ernst.
Apart from several performances of the Bach transcriptions, recordings of Johann Ernst's music include:
- Violin Concerto in B flat major, Op. 1, No. 1,
- Violin Concerto in G major (reconstructed from Bach BWV 592) Simon Standage - violin, Ludger Remy - harpsichord, Weimar Baroque Ensemble, Thorofon CTH2371-72.
- Trumpet Sonata in D major (excerpts) Ludwig Güttler - trumpet Roland Straumer - violin, Heinz-Dieter Richter - violin, Joachim Bischof - cello, Werner Zeibig - double bass, Friedrich Kircheis - harpsichord, Berlin Classics 0090532BC.
- Oboe Concerto in G minor (reconstructed from Bach BWV 983), Corole Wiesmann - oboe, Freiburg Musica Poetica Ensemble, Hans Bergmann - Conductor, Haenssler Classic CD98.408.
- Concerto for 2 Violins in C major (reconstructed from Bach BWV 595 & 984), Andrea Bergmann, Claudia Petersen-Staerkle - violins, Freiburg Musica Poetica Ensemble, Hans Bergmann - Conductor, Haenssler Classic CD98.408.
- He is occasionally referred to as Johann Ernst IV (for example, in the Allgemeine Encyclopädie der Wissenschaften und Künste, Leipzig 1842, II./21., p. 260: article by J S Ersch), implying that he succeeded his father as co-ruler of Saxe-Weimar with his half-brother Ernst August I, both under the regency of their uncle Wilhelm Ernst; this is not well-evidenced.
- Sarah E. Hanks, "Johann Ernst, Prince of Weimar", In Grove Music Online. Oxford Music Online, http://www.oxfordmusiconline.com/subscriber/article/grove/music/14348 (accessed October 29, 2009).
- Christoph Wolff et al.Biography of Bach, Grove Dictionary of Music and Musicians
- Peter F. Williams (1980)The Organ Music of J.S. Bach I: BWV 525-598, 802-805 etc., Cambridge University Press pp.283-5
- John Butt, The Cambridge Companion to Bach p.141.
- John Greene Review of Haenssler Classic CD98.408. Classics Today.com
- Information on recording - BACH, J.S.: Organ Transcriptions Naxos Classics UPC: 730099593625, Naxos Records
- Allgemeine Encyclopädie der Wissenschaften und Künste, 1842
- Butt, John, 1997: The Cambridge Companion to Bach, p 141. Cambridge University Press (digitised)
- Ersch, J.S., 1842, in: Allgemeine Encyclopädie der Wissenschaften und Künste, Leipzig 1842, II./21., p. 260 (digitised) (German)
- Williams, Peter F., 1980: The Organ Music of J.S. Bach I: BWV 525-598, 802-805 etc., pp. 283–5. Cambridge University Press (digitised)