[1][2] A committed monarchist and, until the First World War, well networked internationally with fellow medievalists, his personal diaries, which have been extensively researched and analysed posthumously, provide insights which are enlightening about the times through which he lived, and quite possibly constitute a more important contribution to European historiography than any of his published articles and books on the Medieval centuries.

Cartellieri would much later describe Ranke as "the greatest historian of all peoples and times"[a][9][10] Another early focus of his historical passions, triggered by frequent walks in the Tuileries and to the royal tombs at Saint-Denis, involved the French monarchy.

His parents were providing him with a generous 1,500 Mark annual allowance, and he shunned the dissolute life-style sometimes associated with well-funded students of the period, which left him with substantial funds for buying books.

[15] The lectures of Heinrich von Treitschke covering the principal topical themes of the day, such as the "Jewish question", the church-state rivalries known collectively to historians as the "Kulturkampf" and education reform, also made a lasting impression on him.

[2] Had he anticipated the posthumous publication of his diaries, he might or might not have confided to their pages his explanation that marriage seemed to him to be "still the best way to satisfy certain feelings .... [and] to get hold of a good cook, house keeper and carer"[b][8][20] According to at least one source, Cartellieri was able to benefit from "material support" from his Margarete's father for the rest of his life.

His more notable contacts included Léopold Victor Delisle, Director of the French National Library, and the medievalist historians Denis Jean Achille Luchaire and Charles Petit-Dutaillis.

Of greater importance, as it seemed at the time, was the message he received that permission had finally been granted to start work on building an extension to the University Library in Jena later that year.

As Cartellieri's diaries reveal, the inopportune timing of a magnum opus dealing with the (French) King Philippe Auguste's victory over the (German) Emperor Otto IV at Bovines was only made worse by the battle's seven hundredth anniversary, in May 1914.

According to Matthias Steinbach, Cartellieri underwent an "interior change into an embittered nationalist, content to squander intellectual and heuristic energies in the fight against the enemy and, later, against the Versailles peace treaty".

[40] Steinbach finds that this contrasts starkly with a speech Cartellieri had delivered in June 1914 in his capacity as university prorector, in which he had characterised France and Germany as "siblings at odds over an inheritance" and urged students to "recognise no frontier-posts in the intellectual struggle, but to set out boldly in order to conquer the non-destructive realm of knowledge".

[42] Using the pseudonym "Konrad", Cartellieri contributed, during 1914/15 to Eugen Diederichs's monthly magazine Die Tat, a publication produced in Jena which was devoted to the arts and politics, and which during the war became strikingly nationalistic.

[38] On the other hand, he also did not engage politically, as might have been expected, in Dietrich Schäfer's "Non-aligned Committee for a German Peace" ("Unabhängige Ausschuss für einen deutschen Frieden") or in the ultra-conservative "Fatherland Party" ("Deutsche Vaterlandspartei").

After a long walk that the two men took together in January 1917, Cartellieri confided to his diary that he thought Pirenne "an exceptionally clever man, unfailingly obliging in discussion, but of course subject to the limitations to be expected of any Frenchman".

According to Matthias Steinbach, who has made a study of the matter, there were only three other men in Germany with comparable book collections: the sociologist Werner Sombart, the international economist Joseph Schumpeter and the polymath-sociologist Max Weber.

[49][e] Like many of those who had been appalled by the emperor's enforced abdication, Cartellieri completely rejected the republican regime which during the 1930s became known (in a term originated by Adolf Hitler in a speech of snarling contempt) as the Weimar Republic.

The biographer Matthias Steinbach places him closer to those who acknowledged the Weimar constitution from a sense of what was reasonable under the circumstances than to the die-hard "national-conservative" professors such as Dietrich Schäfer, Johannes Haller and Max Lenz.

During the later 1920s and early 1930s, which was a period of intensifying political gridlock in the parliament ("Reichstag") and polarisation on the streets, Cartellieri generally voted for the DNVP or, latterly, for the conservative-liberal "People's Party" ("Deutsche Volkspartei" / DVP).

[65] But with millions unemployed, street politics polarised and parliament deadlocked by the mutual hatreds of extremism, a few weeks later Alexander Cartellieri used the 1932 presidential election to vote for Adolf Hitler.

Even though it constituted what subsequent generations would identify as a terrorist act by the government, Cartellieri's diary entries show no appreciation of the gravity of what had been done: he welcomed the "decision" and hoped that the outcome would be "a major improvement in general conditions".

[43] The historian Karel Hruza has found frequent negative references in the diaries to Jewish academic colleagues, such as Hermann Bloch, Hedwig Hintze and Ernst Kantorowicz.

In discussing the antisemitic arracks and massacres which erupted in the Rhineland at the end of the eleventh century as part of the build-up to the First Crusade, he shared with readers the assessment that those actions had brought "ruin to many who participated in them and, of course, to many innocent people .... and attracted great disapproval from contemporaries".

[75][84] The historians Matthias Steinbach and Herbert Gottwald conclude that he retained an emotionally fuelled "Nibelungentreue" faith in Hitler to the end, irrespective of the doubts that sometimes surface in the diary entries.

[3] Christian Amalvi, a twenty-first century commentator infers that he was thinking, in particular, of Germany's leading intellectuals, such as Berthold Brecht and Thomas Mann (both of whom are recalled by subsequent generations as high-profile anti-nazis who did indeed escape to the America, respectively in 1933 and 1939).

[3] In 1942 the National Socialists marked his seventy-fifth birthday by dedicating a lengthy article to Alexander Cartellieri in Nationalsozialistische Monatshefte, a monthly magazine produced by the party in Munich.

[98] The work drew on his long-standing interest in the topics covered, but also reflected the author's own far more recent experiences of revolution in Germany following the destruction and military defeat of the "World War".

He attributed Philippe Auguste's hatred of England to "the impressions that the bright boy had taken in, at least in part unknowingly, when he saw how his father's entire being and legacy had been consumed in defending himself against this overmighty enemy".

"It is only right and proper", he wrote in the foreword to his first volume, "to raise world history to the level of a deserving subject for academic study, by not permitting it to say anything that cannot be proven: that is directly or indirectly traced back to the sources".

[8] Steinbach believes that Cartellieri's personal perspective combines an underlying commitment to the conservative-monarchist tradition with Rankean methodology and a certain international awareness unusual in second tier historians.

[113] The publishers presented Cartellieri's diaries as "representative" testimony, providing an insight into the "Mindset of senior German educators" (... die "Mentalität des deutschen Bildungsbürgertums").

[115] In 2014 the western journalist-historian Tillmann Bendikowski produced his popular book "Sommer 1914", in which he tried to show, through the eyes of five very different contemporary witnesses, how Germans experienced the outbreak of the First World War.