|Died||20 December 1936 (aged 60)|
|Known for||Being the second wife and cousin of Albert Einstein|
(m. 1896; div. 1908)
|Children||Ilse Lowenthal Einstein|
Margot Lowenthal Einstein
Fanny Koch Einstein
|Relatives||Hermann Einstein (father-in-law; first cousin, once removed) Albert Einstein (second husband; first cousin)|
Elsa Einstein (18 January 1876 – 20 December 1936) was the second wife and cousin of Albert Einstein. Their mothers were sisters, thus making them maternal first cousins. Further, their fathers were first cousins, making the couple paternal second cousins too. Elsa had the surname of Einstein at birth, lost it when she took the name of her first husband Max Löwenthal, and regained it in 1919 when she married her cousin Albert.
Elsa, the daughter of Rudolf Einstein and Fanny Einstein (née Koch), was born in Hechingen on 18 January 1876.: 146 She had two sisters: Paula (c. 1878–c. 1955) and Hermine (1872–1942). Rudolf was a textile manufacturer in Hechingen. During the regular visits with the family in Munich, she often played with her cousin Albert. In her Swabian dialect, she called him "Albertle". The two parted ways in 1894, when Albert left Germany to follow his family to Milan.
In 1896, Elsa married textile trader Max Löwenthal (1864–1914),: 146 from Berlin, with whom she had three children: daughters Ilse (1897–1934) and Margot (1899–1986), and a son who was born in 1903, but died shortly after birth.: 146,287 They lived together in Hechingen. In 1902, Max Löwenthal took a job in Berlin. His family stayed in Hechingen. She divorced Max on 11 May 1908,: 146 and moved with her two daughters to an apartment above her parents on Haberlandstrasse 5, in Berlin.: 146 She and her daughters reverted to her maiden name, Einstein, after her 1908 divorce.
She began a relationship with her cousin Albert Einstein in April 1912,: 147 while Albert was still married to his first wife, the physicist and mathematician Mileva Marić. Einstein separated from Mileva in July 1914. He sent her with the two sons back to Zürich. Their dedicated divorce was final on 10 February 1919. Elsa married him three and a half months later, on 2 June 1919.
With stepdaughters Ilse and Margot, the Einsteins formed a close-knit family. Although Albert and Elsa did not have any children of their own, Albert raised Ilse and Margot as his own.: 193 They lived in the Berlin area, also having since 1929 a summer house in Caputh in nearby Potsdam.: 203 Ilse also served as Einstein's secretary for a brief period.
Elsa spent most of her marriage with Albert acting as his gatekeeper, protecting him from unwelcome visitors and charlatans.: 190,196 She also was the driving force behind building their summer house.
In 1933, Albert and Elsa Einstein immigrated to Princeton, New Jersey, US. In autumn 1935, they moved to a house at 112 Mercer Street,: 216 bought that August, but shortly afterwards Elsa developed a swollen eye and was diagnosed with heart and kidney problems.: 216 When Elsa was diagnosed, Einstein decided to spend much of his time in his studies. It was stated in Walter Isaacson's book, Einstein: His Life and Universe, that he believed "strenuous intellectual work and looking at God's nature are the reconciling, fortifying yet relentlessly strict angels that shall lead me through all of life's troubles". Thus did Einstein try to escape from his troubles by focusing on work that would distract him from Elsa's dying. Elsa died after a painful illness on 20 December 1936, in the house on Mercer Street.: 216
- Albert Einstein House Princeton
- Genius, a television series depicting the Einsteins
- List of coupled cousins
- Küpper, Hans-Josef (2018). "Short life history: Elsa Einstein". einstein-website.de. Retrieved 18 March 2022.
- Highfield, Roger; Carter, Paul (1993). The Private Lives of Albert Einstein. London: Faber and Faber. ISBN 9780571167449. OCLC 1256489238.
- Isaacson, Walter (2007). Einstein: His Life and Universe. New York: Simon & Schuster. ASIN B000PC0S0K. ISBN 978-0-7432-6473-0. OCLC 76961150.
- Smith, Dinitia (6 November 1996). "Dark Side of Einstein Emerges in His Letters". The New York Times. Retrieved 18 March 2022.
- Jha, Alok (11 July 2006). "Letters reveal relative truth of Einstein's family life". The Guardian. Retrieved 18 March 2022.
- "Albert Einstein's letter to colleague may fetch $5,000 at auction". The Economic Times. 4 December 2017. Retrieved 18 March 2022.
The eldest daughter of Einstein's second wife, Elsa, Ilse Lowenthal Einstein served as Einstein's secretary for a brief period, according to RR Auctions.
- Rieber, Christoph (2018). Albert Einstein: Biografie eines Nonkonformisten (in German). Ostfildern: Jan Thorbecke Verlag. ISBN 9783799512817. OCLC 1048272199.