19th-century Polish Jews

Stanisław (Salomon Naftali) Mendelson (18 November 1858 in Warsaw - 25 July 1913 in Warsaw) was a Polish socialist politician and publicist of Jewish descent. He was an activist of Polish and international workers' movement.
He was one of the main activists and creators of the first programme of the Polish Socialist Party. In 1875-1878 he helped organize socialist groups in Warsaw. In 1878 Mendelson emigrated to Switzerland, and later lived in France and the United Kingdom. He was the co-founder and editor of the first Polish socialist magazines - Równość, Przedświt and Walka Klas.In 1880 he was accused, together with other activists, in a judicial process with socialists in Kraków. In 1882-1884 he organized socialist groups in Poznań and was eventually imprisoned by Prussian authorities. Being a skilled organizer and publicist, Mendelson personally befriended many foremost European socialists - Friedrich Engels, Karl Liebknecht, Eduard Bernstein, Karl Kautsky, Paul Lafargue, Georgi Plekhanov and others.

Izrael Kalman Poznański (25 August 1833–28 April 1900) was a Polish-Jewish businessman, textile magnate and philanthropist in Łódź, Congress Poland (part of the Russian Empire), and the husband of Eleonora Hertz Poznańska. The mausoleum of Izrael and his wife, Eleonora Hertz, on the New Jewish Cemetery has been described as "probably the largest Jewish grave monument in the world". The mausoleum and mosaic covering the inside of the dome were restored in 1993.
Together with Ludwik Geyer and Karol Scheibler, he was counted among the three "Kings of Cotton" in Łódź. His complex of mills in Łódź, Poland, have been turned into the 69-hectare (170-acre) Manufaktura mixed-use development, including a mall, 3 museums, a multiplex cinema, a hotel, and restaurants.

Sofia Sigizmundovna Dzerzhinskaya (born Muszkat; Polish: Zofia Dzierżyńska—Muszkat; Russian: Софья Сигизмундовна Дзержинская—Мушкат; 4 December 1882 – 27 February 1968) was a leading Polish Social Democrat and later Communist politician. During World War II, she was director of the Polish language Tadeusz Kościuszko radio station, broadcasting the communist message into occupied Poland.
From September 1918 through February 1919, Sofia was a member of the Soviet diplomatic mission in Bern. From 1920, she lived in the Soviet Union, in Moscow where she worked as a teacher. In 1922, Sofia worked in the School of Rosa Luxemburg in Moscow, later, 1923–24 at the Communist University of the National Minorities of the West. After that, she worked in the Polish Bureau of the Communist Party of the Soviet Union. From 1939 to 1943, Sofia worked at the Executive Committee of Comintern. In 1969, her memoirs "Lata wielkich bojów: wspomnienia" were published in Poland by Książka i Wiedza publishing house. She died in Moscow in 1968 and was buried at Novodevichy Cemetery.

Aaron Kosminski (born Aron Mordke Kozmiński; 11 September 1865 – 24 March 1919) was a Polish barber, hairdresser, and suspect in the Jack the Ripper case.
Kosminski was a Polish Jew who emigrated from Congress Poland to England in the 1880s. He worked as a hairdresser in Whitechapel in the East End of London, where a series of murders ascribed to an unidentified figure nicknamed "Jack the Ripper" were committed in 1888. From 1891, Kosminski was institutionalised after he threatened his sister with a knife. He was first held at Colney Hatch Lunatic Asylum, and then transferred to the Leavesden Asylum.
Police officials from the time of the murders named one of their suspects as "Kosminski" (the forename was not given), and described him as a Polish Jew in an insane asylum. Almost a century after the final murder, the suspect "Kosminski" was identified as Aaron Kosminski; but there was little evidence to connect him with the "Kosminski" who was suspected of the murders, and their dates of death are different. Possibly, Kosminski was confused with another Polish Jew of the same age named Aaron or David Cohen (real name possibly Nathan Kaminsky), who was a violent patient at the Colney Hatch Asylum.
In September 2014, author Russell Edwards claimed in the book Naming Jack the Ripper to have proved Kosminski's guilt. In 2007, he had bought a shawl which he believed to have been left at a murder scene and gave it to biochemist Jari Louhelainen to test for DNA. A peer-reviewed article on the DNA analysis was published in the Journal of Forensic Sciences in 2019. However, scientists from Innsbruck Medical University have criticised the paper and its conclusions, pointing to a number of mistakes and assumptions made by its authors.