He lectured at the Sorbonne and Oxford,[1] served briefly on the International Committee on Intellectual Cooperation in Paris after World War I,[1] and spent fifteen months imprisoned in Dachau and Buchenwald, where he developed heart disease.

His life and work intersected with those of Sigmund Freud, Carl Jung, Alois Riegl, Gilbert Murray, Karl Popper, Hugo von Hofmannsthal, G. R. S. Mead, Aby Warburg, Fritz Saxl, Gershom Scholem, Oskar Goldberg, Martin Buber, and Walter Benjamin.

At his trial, in which Hugo von Hoffmannsthal testified as a character witness, Eisler confessed to having taken the codex and was ultimately allowed to pay his court costs and avoid jail time so that his family could take him to a sanitarium in nearby Gorizia.

[4] From 1914 until 1917 Eisler served as an officer in Austria-Hungary’s 59th "Erzherzog Rainer" Infantry Regiment, and was awarded the silver medal and was made a knight of both the Order of Francis Joseph and the Iron Cross.

[5] Eisler’s contacts with the "Hamburg School" of art history, which included Aby Warburg and Fritz Saxl and the philosopher Ernst Cassirer, began in the early 1920s.

[6] On 3 December 1922, Eisler went to Hamburg to give a paper titled "Orphische und altchristliche Kultsymbolik" ("Orphic and Early Christian Cult Symbolism") at the Bibliothek Warburg and received spontaneous applause at the end of his lecture.

[7] Writing from the Bellevue Clinic in Kreuzlingen, Warburg, who was much concerned with professionalism and distinguishing himself from the amateur scholars of his day, vehemently opposed Eisler’s invitation.

"[7] At the time, Warburg was suffering from severe depression and was subject to "terrible tantrums and phobias, obsessions and delusions which ultimately made him a danger to himself and his surroundings and lead to his confinement in a closed ward.

However, Eisler accepted the position and moved into a large rented apartment in Paris without first obtaining the permission of the Austrian government, who lodged a complaint with the League of Nations.

A year later he published a shorter English edition titled The Messiah Jesus and John the Baptist According to Flavius Josephus’ Recently Rediscovered 'Capture of Jerusalem' and Other Jewish and Christian Sources (1931).

Eisler drew on an historical practice from the Italian Renaissance called "banco-money" to argue for a dual currency system that would create an effective negative interest rate by removing the zero lower bound.

Following the Anschluss in March 1938, Eisler wrote to Oxford asking about being appointed to the Wilde Readership in Comparative and Natural Religion, thereby gaining a way out of Nazi-controlled Europe.

"[21] In September 1939, Eisler wrote to a friend about his time in the camps:[It] may interest you that I have had some very fruitful and comforting discussions with one highly educated and intelligent member of the primitive Christian adventist community of the so-called Biblical Scientists, the members of which are mostly in the German concentration camps (about 500 in Buchenwald) and more cruelly treated even than the Jews because they believe Hitler to be the foretold Anti-Christ, the Kingdom of God as a political organisation to be realized here on earth as a reign of justice and loving kindness and because they refuse military service.

I was greatly surprised to learn that this man who had studied Hebrew and Greek as well as theology in order to be a preacher and teacher among his brethren (they have no clergy) should have read my German ΙΗΣΟϒΣ ΒΑΣΙΛΕϒΣ and derived from it what he felt to be the strongest possible confirmation of his own and [the founder of the sect] Judge Rutherford’s interpretation of the gospels!

[22]After his release, Eisler made his way to England via Italy and Switzerland and arrived in September 1939 to find that Oxford had appointed the Anglo-Catholic philosopher and historian of religion Edwin Oliver James to the readership in his absence.

But James, Englishman though he was, declined to give up his post, and so the university made a concession to Eisler, allowing him to deliver his scheduled 1938 lectures on "the pre-Hellenic populations of Crete and the Aegean" in the Michaelmas terms of 1939 and 1940, and to receive a stipend of £156.

The same month his wife finally joined him in England, Eisler was sent to another prison camp, this time by the British government, who had begun interning Jewish refugees on the Isle of Man.

I have therefore decided to give you an exact survey of the facts, although I feel sure that the only result will be to convince you more than ever that I am a very square peg impossible to fit into any of the well-rounded and polished but rather narrow holes available in this country… I have arranged with the Oxford professor of anatomy who has very kindly undertaken to utilise for teaching purposes and the benefit of science what I shall leave here when I finally depart from this queer world and thus to relieve my guarantors from what I understand might be a final expenditure of at least [£40] to close my account.

The second one, written by his friend Cyril Goldsmid (the scion of a powerful Anglo-Jewish family) describes him as "possessed of encyclopedic knowledge," but "entirely devoid of intellectual arrogance.