While on the topic of Ernst’s descendants, the Manchester Courier and Lancashire General Advertiser, 6th June 1895, p.10, contains an interesting article about two musicians described as Ernst’s nieces – the violinist and harpist Marianne and Clara Eissler (born in 1865 and 1868 respectively). Their father, Hermann Eissler, was a professor of science at the university in Brno, but when he died, his wife moved to Vienna so her daughters could study at the Conservatory which both entered aged 7. Marianne studied with Professor Karl Hessler, and acquired, by the age of 9, a reputation as a local prodigy; while Clara studied with the Harpist Zamara before moving to Paris to complete her education with Hasselmanns. By the age of 17, the elder sister Marianne was playing at the Philharmonic concerts in London, and both sisters eventually secured official positions at the court of Saxe-Coburg-Gotha, and played several times for the British royal family.
The sisters enjoyed a considerable reputation. Joachim considered Marianne second only to Madame Neruda (Lady Hallé) amongst lady violinists; she appeared regularly at Amelie Joachim’s concerts; and was a friend and collaborator of Adelina Patti’s. It is now thought that Marianne (rather than Wilhelmj) is the violinist on Patti’s recording of Gounod’s Ave Maria (which can be found on YouTube). Saint-Saëns dedicated his Fantasy for Violin and Harp in A major op.124 to the Eissler sisters, and Marianne was the dedicatee of Sarasate’s Le Rêve op.53.
The connection with Ernst is only mentioned in the Manchester Courier article mentioned above and I have my doubts as to whether they were Ernst’s nieces, although it is quite likely they were more distantly related to the violinist. Ernst’s sisters seem to have been born between 1806 and 1809, while his half-sister was born in 1788. This clearly makes them too old to be having children in 1865-8.
More information about all the Eissler sisters (there were at least three) can be found here.