Agnes Street-Klindworth, also Agnes Denis-Street,[1] was the illegitimate daughter of journalist, actor and diplomat Georg Klindworth (1798–1882) and a Danish actress named Brigitta Bartels (1786–1864).
[2] Shortly after she began having piano lessons with Franz Liszt, whom she befriended and had an affair with.
They maintained a vast correspondence between the spring of 1855 and 1861, when he finally took up residence in Rome.
Her second child with her husband Captain Ernst Denis-Street was named Charles, born on 18 July 1855.
[4] Her third child was named Fernande (16 December 1856 – 23 August 1857), daughter of the composer and revolutionary activist Ferdinand Lassalle.