When did actually start the "final Solution" according with Exterminationists?
To follow, later, I will list others major dispcrepancies about the dates on which Nazis supposedly started the "Final Solution". The "unanimity" is far from being reached on that important point. A video by Vincent Reynouard stresses that lack of consensus while giving different dates advanced by differents authors for the "start" of the extermination of all European Jews.https://archive.org/details/VincentReyn ... reEnFrance
First Dates advanced
- before WWII
according with "Intentionalists"
who invoke the discourse of Hitler on January 30, 1939.
- on July 31, 1941
according with some "Functionalists"
who base their analysis on the Göring's letter to Heydrich.
- During Summer 1941
according with the IMT Judgment at Nuremberg
[...]In the summer of 1941, however, plans were made for the " final solution" of the Jewish question in all of Europe. This " final solution " meant the extermination of the Jews, which early in 1939 Hitler had threatened would be one of the consequences of an outbreak of war, and a special section in the Gestapo under Adolf Eichmann, as head of Section B4 of the Gestapo, was formed to carry out the policy.
The plan for exterminating the Jews was developed shortly after the attack on the Soviet Union. [...]http://avalon.law.yale.edu/imt/judwarcr.asp
This judgment was based essentially on the Höss' confession in which he wrote that Himmler had revealed to him during the summer 1941 that Hitler had decided to exterminate the Jews.
That thesis prevailed during several decades. Gerald Fleming
in 'Hitler and the Final Solution' (1982) as well as Raul Hilberg
in "The destruction of European Jews (1985) support that version
- on January 20, 1942
according with historians who invoke the Wannsee Protocol.Other dates advanced for the "well established" Holocaust narrative
- end of September 1941
according with Christopher R. Browning
in 'The Origins of the Final Solution : The Evolution of Nazi Jewish Policy, September 1939 – March 1942' (2004). In that book, the author executes the Höss' confession by writing that the alleged mention by HImmler of an Hitler's order for the destruction of the Jews was not credible. Browning stresses the visit of Himmler to Globocnik in Lublin on July 20, 1941 where Globocnik received the order for constructing a big concentration camp (Majdanek). Browning "thinks" that it was very probably at the end of September
that Heydrich informs Eichmann about the Hitler's decision in favor of the "physical destruction" of the Jews of Europe and send him to Lublin in order to report on the Globocnik's moves.
Only at the end of October did the various strands of Jewish policy again come together. creating the initial outline of the course Nazi Germany was embarking upon. Until then the Nazi leadership envisaged solving their self-imposed Jewish question through expulsion, accompanied by no small amount of outright killing and attrition, in order to create a German empire free of Jews. Thereafter, the vision was clearer. No Jews were to escape the German grasp, and no Jews were in the end to be left alive. If before August 1941 the Jewish question was to be solved "one way or another", after October it was to be solved in one way -- through the death of all Jews. (p.318)
- Early December 1941
according with an Essay by Gord McFee
(1998?). The author alleges two Recently Discovered Documents cited in the German Newspaper Die Zeit
The two recent discoveries are:
1. The first is a diary entry by Joseph Goebbels of December 12, 1941. It runs as follows:
Bezüglich der Judenfrage ist der Führer entschlossen, reinen Tisch zu machen. Er hat den Juden prophezeit, daß, wenn sie noch einmal einen Weltkrieg herbeiführen würden, sie dabei ihre Vernichtung erleben würden. Das ist keine Phrase gewesen. Der Weltkrieg ist da, die Vernichtung des Judentums muß die notwendige Folge sein.
With respect of the Jewish Question, the Führer has decided to make a clean sweep. He prophesied to the Jews that if they again brought about a world war, they would live to see their annihilation in it. That wasn't just a catch-word. The world war is here, and the annihilation of the Jews must be the necessary consequence. 
2. The second is a note in his own handwriting by Reichsführer-SS Heinrich Himmler in his soon to be published diary of a meeting he had with Hitler at the latter's Headquarters (Wolfsschanze) on December 18, 1941. The notes are simply: 
Judenfrage / als Partisanen auszurotten
Jewish Question / to be exterminated like the partisansHitler Personally Ordered The Final Solution
Most experts have agreed that an action on the magnitude of a mass genocide, with the resultant possible ramifications, could not have proceeded without Hitler's personal approval. Until now, no written decision from Hitler has been found, although there are compelling indications that a verbal decision was certainly given.  The recent discoveries cannot be called a written decision (which, if it ever existed, was almost certainly destroyed by the end of the war), but they are certainly unequivocal confirmation that a clear decision was taken by Hitler. Even better, they help pinpoint the time it was taken.The Decision Was Made At The End Of 1941The new evidence strongly suggests that Hitler decided once and for all, in early December 1941, to exterminate all of European Jewry.
That squares with the words, "aspired final solution" in Goering's order to Heydrich of July 1941, and helps to explain why the Wannsee Conference took place so long after the Goering order had been issued, that is, the final order had still not been given in July 1941.
7. Die Zeit, edition of January 9, 1998; AFP, dispatch of January 14, 1998.
9.By far the best treatment is Gerald Fleming, Hitler and the Final Solution, University of California Press, Berkley, 1984.
- December 1941
according with Laurence Rees
in "Auschwitz : The Nazis & The 'Final Solution'" (2005)
That same month, November 1941, Hitler, in a discussion with the Grand Mufti of Jerusalem, who had fled to Berlin, said that he wanted all Jews, even those not under German control, 'to be destroyed' [...]
But, this does not mean that Hitler and the other leading Nazis took a firm decision in the autumn of 1941 to murder all the Jews under German control. In the first place, there simply was not yet the capacity to commit such a crime. The only killing installations under construction in November 1941 were a gas van facility at Chelmno and a small fixed gas chamber installation at Belzec. (p. 110)
Much more important than the conversations at Wannsee were the discussions Hitler held in December 1941. If proper minutes were available of the Führer's meetings with Himmler during that period we would truly see the bleak landscape of the mind that made all this suffering. (p.119)
- At the turn of summer 1941
, according with French Historian Joël Guedj
in "Introduction à l'Histoire de la Shoah"(2010). In this book, the author comes back to a more traditional version without any explanation:
La decision de procéder à la liquidation physique de tous les Juifs du continent européen est prise au tournant de l'été 1941. Le 31 juillet 1941. Göring adresse à Heydrich l'ordre écrit lui enjoignant d'entreprendre des préparatifs pour aboutir à la "Solution finale" (Endlössung) de la question juive.
The decision to proceed with the physical liquidation of all Jews on the European continent is taken at the turn of summer 1941. On July 31, 1941, Göring addresses to Heydrich the written order directing him to undertake preparations in order to achieve the "final solution "(Endlössung) of the Jewish question.
- End of April 1942
, according with French Historian Florent Brayard
in "Auschwitz, Enquête sur un complot Nazi" [Auschwitz, Survey on a Nazi conspiracy
Confortant les résultats de mon livre sur la "solution finale", elle revient en effet à décaler d'un trimestre, de fin janvier à fin avril 1942, l'inclusion des juifs allemands dans le projet, déjà observable ailleurs à l'Est, de mise à mort des JUifs à court terme. L'autorisation de meurtre des Juifs allemads (et probablement plus généralement des juifs de l'Ouest) fut, comme on l'a dit, immédiatement mise en oeuvre sur le terrain: au début du mois de mai à Chelmno, à la mi-mai en Haute-Silésie avec les premiers convois vers Auschwitz, au début du mois de juin pour les Juifs allemands et slovaques déportés dans le Gouvernement général. (p.286)
Confirming the results of my book on the "final solution", it means, in effect delaying of a quarter, from late January to [color=#FF0000]late April 1942, the inclusion of the German Jews in the project, already noted elsewhere in the East, of killing the Jews in the short term. Permission to murder German Jews (and probably more generally Jews of the West) was, as we said, immediately implemented on the field: at the beginning of May in Chelmno, in mid-May in Upper Silesia with the first convoys to Auschwitz, in early June for German and Slovak Jews deported to the General Government. (p.286)[/color]
In his video, Vincent Reynouard concludes:
En vérité, le problème capital est le suivant: ces divergences entre historiens démontrent qu'en ce qui concerne l'holocauste, le dossier est vide, désepérement vide. Les historiens n'ont trouvé ni ordre d'Hitler d'exterminer les juifs, ni plan pour mener à bien cette extermination, (ne parlons pas de le Conférence de Wannsee où rien de précis n'a été décidé), no organisme centralisateur, ni budget, ni organe de contrôle.
Car dans le cas contraire, si ils avaient retrouvé toutes ces pièces, un chronologie précise de l'holocauste aurait pu être établie depuis bien longtemps maintenant. Or, qui peut croire qu'un massacre de 6 millions de personnes perpétré sur plusieurs millions de kilometres carrés ait pu être réalisé comme ça, sans organe de contrôle, sans plan sans budget sans rien.In fact, the major problem is the following: these divergences among historians regarding the Holocaust show that the folder is empty, hopelessly empty. Historians have found neither order from Hitler to exterminate the Jews, nor plan to carry out this extermination, (no need to talk about the Wannsee Conference where nothing specific has been decided), nor central organization, nor budget and nor supervisory body. Because otherwise, if they had found all of these pieces, a precise chronology of the Holocaust could have been established for a long time now. But who can believe that a massacre of 6 million people perpetrated over several million square kilometers could be done like that, without controlling body, without a plan, without budget, without nothing.https://archive.org/details/VincentReyn ... reEnFrance