The Rebbe’s Brother, the Secret Mission:
Reb Yisroel Aryeh Leib Schneersohn Z”L
and the Hidden Foundations of Israel’s Nuclear Program
Introduction:
It is with a sense of awe and reverence that we present a reevaluation of the life and legacy of Reb Yisroel Aryeh Leib Schneersohn Z”L—known affectionately as Reb Leib—the younger brother of the Lubavitcher Rebbe, Rabbi Menachem M. Schneerson. Long thought to have lived a quiet life in academia, recent revelations and personal testimonies suggest that Reb Leib played a key role in one of the most sensitive and critical developments in the history of the modern State of Israel: the foundation of its nuclear program.
His sudden passing on 13 Iyar 5712 (May 8, 1952), at just 43 years old, came shortly before the formal establishment of the Israel Atomic Energy Commission (IAEC)—a curious and possibly significant timing. What was previously understood as a purely scientific and educational journey to Liverpool, England, is now seen in a dramatically different light: part of a covert, high-level mission to ensure the long-term security of the Jewish State.
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Reb Yisroel Aryeh Leib Schneersohn Z"L, the younger brother of the Lubavitcher Rebbe, Rabbi Menachem Mendel Schneerson, remains a largely enigmatic figure in Jewish and Israeli history. Known for his deep scholarship and private nature, some sources and testimonies suggest that he played a quiet but pivotal role in the formative years of the State of Israel — possibly including involvement in Israel’s early nuclear efforts.
While mainstream historiography has not yet fully examined his contributions, tantalizing fragments from declassified documents, oral history, and certain memoirs hint at his participation in strategic intellectual or scientific circles. Some hypotheses posit that he may have served as a behind-the-scenes connector between religious Jewish communities and secular Israeli institutions during the state’s formative years.
If one considers the clandestine nature of Israel’s nuclear program — developed under a strict veil of secrecy and aided by scientists, foreign liaisons, and discreet intermediaries — the presence of a discreet, highly educated figure like Reb Yisroel Aryeh Leib becomes more plausible. Notably, he lived in the United Kingdom and later in the Land of Israel, reportedly maintaining connections with key figures in Jewish and modern Israel's intellectual life.
Could he have served as a religious or ethical advisor, a liaison between worlds, or perhaps even contributed scientifically? Without sensationalizing, this article explores what we know, what we suspect, and what remains to be uncovered about his legacy — and why it matters today.
B”H
A Paper on The Rebbe’s Brother Reb Yisroel Aryeh Leib Schneersohn Z"L
"The Brother Who Devoted His Life for Jewish Security"
It is of great importance to point out that “The Israel Atomic Energy Commission” was officially established on June 13, 1952 - a few day after the Shloshim the 30 day mourning period for The Rebbe’s brother Reb Yisrael Aryeh Leib Schneersohn - known as “Reb Leib” who passed away suddenly at the early age of 43 while on a very successful super spy mission in the UK to arm Israel with Nuclear Arms.
(see
https://en.wikipedia.org/wiki/Israel_Atomic_Energy_Commission )
By way of introduction, it is very important to read more about the life of Reb Leib, especially of his time living in Berlin 1931-1933 along with The Rebbe and Rebbetzin Chayah Mushkah Schneersohn, his brother and sister in law.
This was at a time when both the Rebbe and his brother Reb Leib were both studying the sciences with some of the top minds in the field, including many who would go on to develop Nuclear power for different countries. In fact, many years later the Rebbe made sure that his mother was informed that his brother Reb Leib was working for the Atomic Commission and could not receive visitors. (See more in this article : https://www.iggudhashluchim.com/templates/articlecco_cdo/aid/4710012/jewish/An-Overview-on-the-Life-of-Reb-Yisroel-Aryeh-Leib.htm )
Here is a dramatic revelation that puts in a completely different light the work of Reb Leib -who went by the pseudonym Mark Gurari- in England in his last years.
There are many references to his work online in sites such as Google Scholar including his work with scientists in Liverpool who were “Ahead of their time” such as Dr. Herbert Frohlich who mentions him in his works.
https://en.wikipedia.org/wiki/Herbert_Fr%C3%B6hlich
From an audio recording from 1969 was just recently uncovered we hear the phenomenal quote:
“He is one of the most important people that Ben Gurion sent in to England with regards to The Atomic Mission of Israel”
In 1934, the Rebbe's brother, Reb Leib moved from Berlin where he was studying in the Academia and living alongside his brother the Rebbe for around two years and he made Aliyah and moved to the Holy Land. There are great Torah letters that their illustrious father Rav Levi Yitzchok Schneersohn sent to both of them at that time.
In Spring 1950, he, his wife and their daughter moved to Liverpool, England. There they lived until his passing two years later on the 13th of Iyar 5712 - May 8, 1952.
Up until now it was clear that the reason for his move to England was to complete his studies there.
We know that a fellow Chabadnik from childhood, who later visited the Rebbe and assisted greatly in the Rebbe’s work - Mr. Zalman Shazar was very involved and helped alot in the matter of his move to England because of the importance of his top secret vital mission of which Israel and Jews keep on benefiting from this work of Reb Leib.
Shazar who was the President of Israel 1963-1973, was then the Minister of Education of Israel.
( see https://en.wikipedia.org/wiki/Zalman_Shazar )
This move of Reb Leib received the blessings and instructions including funding from the previous Rebbe.
(see Letters of the previous Rebbe, volume 13 page 454. https://beta.hebrewbooks.org/reader/reader.aspx?sfid=31605#p=473&fitMode=fitwidth&hlts=&ocr= )
“My dear family member, very talented Chosid who fears God, Mr. Leib,
In response to your letter that you decided to move to Britain to be involved in your academic work, with regards to your science - perfecting your science and your academics.
[ there are three dots in the letter published by Kehot “...” meaning there was confidential information in the Rebbe RAYATZ’s letter to Reb Leib that was not allowed to be published]
It's very interesting to me that you are bringing with help of Hashem Blessed be He the beauty of Shem into the tent of Yaphet”
In continuation, the Rebbe RAYATZ requests him to look into translating books of the teachings of Chabad philosophy beginning with the book of Tanya, into English.
“A free translation with contextual notes to understand the matters and their content.”
In the work Rav Moshe Oreenstein was doing in researching one of Reb Leibel’s favorite songs Der Pilpul, which Reb Leib taught was a song composed by the Alter Rebbe, founder of Chabad.
(See https://www.chabad.org/library/article_cdo/aid/110437/jewish/The-Alter-Rebbe.htm )
(And for the Yair Kalev rendition of this powerful song, see https://www.youtube.com/watch?v=xPkQGOeOf8s )
Rav Orenstein wrote how in a Sher recording, he heard many hours of the voices of the people of their city Yekatrinislav now Dnipro, Ukraine reminiscing memories in this gathering that they had - amongst old friends.
There's also a recording where you can hear the voices of a gathering that happened in honor of Mr Yeshayahu Sher, with connection to his transitioning from being the director of “The school for children of workers” in the year 1969. Amongst those who participated in this gathering, was also the mayor of the city Rehovot, Israel.
The speakers expressed a phenomenal respect to this person, to his principles, to his uprightness, to his great many talents and principally of his being a man of education of the highest level.
From this recording it is obvious that Mr. Sher is an extremely distinguished, deliberate and accomplished person.
This is a very interesting recording. This was a group of people that spoke in academic Hebrew; but they laughed in Yiddish - the language that was seemingly easier for them to express themselves.
Parenthetically, when Rav Orenstien was searching to learn more about Mr. Sher, he found great respect from his students. one writes: “A phenomenal man of education” another one says “He was a one in a generation director and organizer” another one said “He didn't only teach us the Tanakh, he taught us to love the Tanakh” There was more and more like this.
Amongst those speaking in that recorded gathering was also Mr Sher himself. It is a riveting talk for around 40 minutes. Every word- counted. At the end of his talk there is a huge surprise - an explosion in Double entendre.
Mr Sher described how he made his way into being an educator when he didn't know how to use his talents, because he has many different talents; He is a brilliant artist. He has phenomenal musical talents. He has a great talent for philosophy and more and more.
He didn't know where he needed to turn and focus. In order to share his problem and ask for help, he turned to his dear old childhood friend Reb Leib Schneersohn, the brother of the Rebbe. Reb Leib described him in Russian saying: “You have many, many talents but they are not yet developed.”
Then to show how important the words of Reb Leib are to his listeners at the gathering, Sher added the following statement which is very, very mysterious. “He is one of the most important people that Mr. David Ben Gurion (Prime Minister of ISrael 1948-1954, 1955-1963) sent to England with regards to the Israel Atomic Commission - to produce Israel’s Nuclear Power and Nuclear Weapons.
We can also take from what he wrote in his diary that he wrote and after that it was printed many times also as an addition to Rav Orenstiens book “Abba II”.
We don't know how Mr. Sher knew about this. One thing is clear: According to his diaries and notes and also from the tone of his speech he had a phenomenal respect and love for the Rebbe's brother; they shared a great mutual love and friendship.
The 22 pages that he wrote in memory of Reb Leib his dear friend, are like a thousand witnesses of the great inner respect that he felt towards him
It's also important to point out that on this recording Mr. Sher points out that he doesn't know for which specific goal Reb Leib was sent by Ben Gurion to England. He just knows enough to say that his voyage was on a security mission in order to advance the nuclear program of Israel.
Reb Leib and his family moved to Liverpool, UK in 1950 and he passed away in 1952 there.
In Fall of 1947 Reb Leib was already thinking of moving to Britain, as the previous Rebbe wrote to him in 1947 - but it didn't happen right then. In the meanwhile, the state of Israel was established and with it - a security mission of the highest level. Two and a half years later in the summer of 1950, it actually materialized this time.
Indeed, Reb Leib’s academic and scientific work was only a cover up for the true reason: To establish nuclear power and weapons for Israel.
We don't know how to explain why Mr Sher revealed this in that gathering. This is 1969. 16 or 17 years after the passing of Reb Leib. It's possible that then, there was no problem to point this out in a gathering amongst friends.
It wasn't a secret at all to Mr Sher, and as we said before; he didn't know what was Reb Leib’s exact part in this daring mission: Achieve Nuclear Power for Israel and the Jewish Nation.
The wisest of all men, King Solomon writes “Give something to a wise person and they'll become even wiser”
The central question here is: How is England connected with the Israeli nuclear program?
Here's some background: Right after the war of independence of Israel in 1948, the first Prime Minister of Israel Mr. David Ben Gurion started working towards the nuclear program of Israel.
He reached the conclusion that there's no other way from a military perspective to deter the Arab nations that surrounded our country from all sides from their attempt to just completely destroy it. He saw this option as the key to preventing war. Ben Gurion thought that if the Arabs will, God forbid, receive the atom bomb this will place the country of Israel in a very existential and immediate danger.
Therefore, Ben Gurion believed that we have to do whatever is possible to have nuclear weapons before them. There were many important people who argued against him, but Ben Gurion was very firm and convinced in his opinion, so that already at the beginning of the establishment of the state of Israel, Israel began a campaign: a very complicated determined effort to acquire nuclear power and arms.
This was a very bold campaign and some people may say it was very brazen for a country the size of Israel to endeavor.
Beginning in the 50s and throughout the years Israel kept in secrecy and denied in public its Nuclear capabilities and power. Even to this very day it is very quiet.
In actuality, this is an open secret that Israel was the 6th country - -or earlier than that - in the world that had nuclear weapons.
Why England?
The United States was the first country that achieved actual nuclear arms, this happened in 1945. Four years later, the Soviet Union entered into this very small group of countries that have nuclear weapons.
In the course of the Second World War, there was an agreement between the US and the UK to share with each other all information that they would gather with regards to developing Nuclear Arms.
After the Americans achieved it in 1945, the American government began to work towards having an international monopoly on Nuclear Arms - which brought the US to stop sharing Nuclear information with British scientists and with the British government.
The British were not happy with this and the UK began their own independent nuclear program. In the hands of many researchers in the British Empire there was already a lot of knowledge in this area, thanks to a lot of work over many years together side by side with American researchers and scientists.
Five years later in 1952, Great Britain was the third country in the world to have Nuclear Arms.
Reb Leib Schneersohn came to Great Britain in the eye of the storm of the UK’s advancing their nuclear program and it it makes sense to estimate that it came to learn about their nuclear program to effectively employ this nuclear program in Israel: The time had come for Reb Leib to advance the nuclear program of Israel in the critical years of establishing this program in Israel.
In this same era the British Empire was ruling over most uranium deposits in the world: Australia, Canada and South Africa.
(See https://world-nuclear.org/information-library/nuclear-fuel-cycle/mining-of-uranium/world-uranium-mining-production.aspx)
Acquiring Uranium may also have been an integral part of the goal of Reb Leib in England.
How did Reb Leib penetrate the inner recesses of Britain that was then known as “The holy of holies”? To complete the puzzle here is something Rav Orenstein heard from Rabbi Eliyahu Shvicha, a Shliach of the Rebbe in North Tel-Aviv.
A clear indication to this riveting revelation that we have here in the diary of Mr. Sher is that he mentions Mr Yona Kesse - he was also from the USSR and he also was the same age of Reb Leib and Mr. Sher. Mr Kesse also came to Israel and through the course of years he was also a member of the Knesset
See https://en.wikipedia.org/wiki/Yona_Kesse
We learn from the Sher diary that there was a friendship between Mr. Kesse and Reb Leib.
A few years ago, Rav Shvicha met the son of Mr Kesse, Zvi Kesse who told him that he heard from his father that one time Reb Leib and his father Mr. Kesse met Reb Leib in Tel Aviv and Kesse asked Reb Leib what he's up to and Reb Leib in his trademark modesty told him that he sent an essay with regards to Nuclear Physics to the British empire's Atomic Commission and because they really appreciated his essay he's been invited to join their committee and he's planning to move there be part of their Atomic Commission.
So now there's a very high reason to believe that once Reb Leib received this mission from the Prime Minister of Israel this was the way Reb Leib got into the inner recesses of the British Empire, being a member of their Atomic Commission
Rav Orenstein also interviewed Mrs Carmela Kesse, second wife and widow Mr. Yona Kesse. Carmela was born in 1927 and she had a very lucid and clear mind and spoke very fluently and wisely - but even then it was hard for her to remember details of what we're speaking about here. However, she remembered with great clarity the great respect that her husband had for the three brothers, the sons of the Rabbi of Yekaterinoslav, sons of the great Holy Rabbi Rabbi Levi Yitzchok Schneersohn the Rebbe's father.
“All three brothers were phenomenal scholars and geniuses of the highest level”
She didn't remember the details of the meeting that her husband had with Reb Leib that took place more than 70 years ago before the interview.
It's also important to point out Mr. Kesse’s fascinating description of the other brother of the Rebbe, Reb Berel HYD. “He was a phenomenal Torah scholar, he was fluent in the entire Torah especially the whole Talmud -you were able to put a needle on any page and he could tell you what is written on that same place on the page many pages afterwards and many pages before that exact spot on the page.
Tragically, Reb Berel had a chronic physical ailment and he was hospitalized near his hometown now Dnipro for a while until he was murdered by the Nazis along with many other patients from the hospital, HaSHem should avenge their blood.
How did Ben Gurion get to know about and recruit Reb Leib?
Rav Orenstien interviewed the daughter of Mr Sher, Mrs Tzivia Greenspan. Her husband Professor Greenspan was also a member of the Nuclear Energy Committee of Israel.
First of all, she says that if her father said that Reb Leib was one of the most important people in Israel's nuclear program he knew exactly what he was talking about “He was very deliberate in his nature and the three years of his close friendship with Reb Leib Schneersohn made a very deep impression and influence on him and all of his life he loved going back to those good old days that he had with Rebbe's brother Reb Leib in Yekaterinoslav”. She adds: “my father was very proud of this friend of his. He prided himself many times that Reb Leib was the first scientist in the Weizmann Institute for science in Israel. He was invited to be part of the first group of scientists of the Weizmann Institute for science established in 1934 the year the Reb Leib came to Israel.
He was the first scientist in the institute.
The world famous Weizmann Institute for science was established by Chaim Weizmann who later became the first president of Israel. He set up a special research team that was the base of manufacturing chemicals in Israel.
Weizmann was very involved in searching for, recruiting and placing the scientists that worked in this institute in the first few years of the institute.
Now it's clear that Rabbi Leib was the first of the scientists of the Weizmann Institute.
In a different diary entry, Sher writes about his meeting with Rabbi Leib on CHanukkah 1936. This is two years after they came to work in the Wiseman Institute.
He describes with unlimited emotion his reunion with his childhood friend Reb Leib. “All the time I was looking forward to seeing him again. I came to the store I came inside and there stood Reb Leib and I right away recognized him. We hugged, he brought me into his store and he told me “I am now involved in a special project in a very intensive way and I think it'll take a few years for me to actually develop the results of what I'm working on.
This was a clear indication to the knowledge of Mrs Greenspan, Mr Sher's daughter, that the main occupation of Reb Leib was his research in the Weizmann institute.
At the head of this institute that then was called The Daniel Sieff Institute, was Professor Ernest David Bergmann who was the head of the institute.
Bergmann was a professor of organic chemistry and he's considered to be the father of the nuclear program of Israel.https://ahf.nuclearmuseum.org/ahf/profile/ernst-david-bergmann/
And https://en.wikipedia.org/wiki/Ernst_David_Bergmann#Scientific_career )
Bergmann also came to Israel at the request of Chaim Weizmann to work in this institute. That was just over a year after Reb Laib came to Israel.
With the establishment of the state of Israel in 1948, Bergmann was the scientific adviser to the minister of defense and the prime minister of the time, Mr. David Ben Gurion and for 14 years he served as the chairman of the Atomic Energy Commission. Now it's clear who introduced Reb Leib to David Ben Gurion
Now we have another interesting addition: With the establishment of the state of Israel, Bergmann was amongst the founders of the scientific unit in the military. This unit was a special unit in the Haganah and the later the IDF that was made up of many scientists and engineers and involved many different military matters that required knowledge in many different sciences.
This unit was established with the active involvement of Ben Gurion who believed that the wars of Israel will be won with HaSHem’s Help with Jewish genius. From this Military science unit many important projects were produced - from this scientific unit of the military which made a great advantage in all of Israel’s wars.
There's another man who is involved in the umbilical cord of the nuclear program, Israel Dostrovsky (see https://en.wikipedia.org/wiki/Israel_Dostrovsky )
In 1948 Dostrovsky established the division of research of isotopes in the Weizmann Institute and also “Unit #3” in the military unit of science of the IDF that was working in the beginning of the research of Israel's Nuclear program. Dostrovsky was part of the first commission of Atomic Energy that was established by Ben Gorion.
Once again Ben Gurion had many ways to hear about Reb Leib Schneerson.
It makes more sense to posit that Bergmann who worked together with Reb Leib since the beginning of the Weizmann Institute knew Reb Leib really well.
It makes a lot of sense to posit that if Reb Leib Schneerson would not have passed away in his youth only at 43 years of age we would have heard his name earlier as one of those who brought the Nuclear program to Israel.
The essay that Reb Leib sent to the Atomic Commission of the British Empire was really a cover up for the true goal:
The security of Israel and of the entire Jewish Nation!
There's another anecdote: A short while before the passing of Rabbi Leib Schneerson he had a very important private talk with the Chief Rabbi of Liverpool, Rabbi Zalman Plitnick who was a personal student of the great Chafetz Chaim - for around two hours.
(See https://en.wikipedia.org/wiki/Yisrael_Meir_Kagan )
https://www.allertonshul.org.uk/Allerton%20Synagogue,%20a%20short%20history.pdf https://www.geni.com/people/Rabbi-Zalman-Plitnik-A-B-D-Liverpool/6000000011524401337 )
Later, Rabbi Plitnik said that he cannot reveal the details of this conversation. To this very day, they're still secret and confidential, although he said that he would reveal the details only to the Rebbe himself, Reb Leib’s brother.
Rabbi Avremi Kievman who's a Shliach of the Rebbe to Liverpool relates that in the 1980’s, Reb Yankel Plitnik the son of Rav Zalman Plitnik came together with another person to visit the Rebbe.
( see https://www.youtube.com/watch?v=1JkDe0iHThw
And https://www.israelnationalnews.com/news/291235 )
This was at the Minchah - afternoon services which was in the small synagogue in 770. The fellow who came with him had visited the Rebbe before, and when the Rebbe passed by them he smiled at them. This other fellow introduced his friend Yankel Plitnik to the Rebbe, saying “this is Yankel Plitnik”,
The Rebbe right away responded “I am very grateful to you, you deserve a big thank you for your father. Your father met my brother and helped him. Thank you very much, Yasher Koach!”
From this it's clear that Reb Leib dedicated his life for the security of the Jewish people in Israel and all around the world with humility and secrecy as was his way. With enough secrecy that this didn't come to the open for more than 70 years after his passing in 1952.
May his memory be for a blessing and may we fulfill the Rebbe’s special request to dedicate ourselves to the Jewish Academia to bring them closer to HaShem.
May his inspiration propel all of us to fulfill our personal missions that HaSHem has charged us with and the united mission: to bring Moshiach Now!
Translated from Hebrew with additions By Rabbi Mendy Cunin, Chabad of Larchmont from an essay in Hebrew in the Kfar Chabad Magazine by Rabbi Moshe Orenstein.
For more about Reb Leib Schneersohn and his family please see:
https://anash.org/resource-site-om-rebbes-brother-launched-his-yahrzeit/
https://chabad.info/magazine/342310/
https://old2.ih.chabad.info/#!g=1&url=article&id=68627
https://anash.org/the-rebbes-brothers-homes-in-berlin-tel-aviv-and-liverpool/