The Night of the Long Knives , sometimes called "Operation Hummingbird " or in Germany the "Röhm-Putsch," was a purge that took place in Nazi Germany between June 30 and July 2, 1934, when the Nazi regime carried out a series of political murders. Leading figures of the "left-wing" Strasserist faction of the Nazi Party, along with its namesake, Gregor Strasser, were murdered, as were prominent conservative anti-Nazis (such as former Chancellor Kurt von Schleicher and Gustav Ritter von Kahr, who had suppressed Hitler's Beer Hall Putsch in 1923). Many of those killed were members of the Sturmabteilung (SA), the paramilitary Brownshirts.

Adolf Hitler moved against the SA and its leader, Ernst Röhm, because he saw the independence of the SA and the penchant of its members for street violence as a direct threat to his newly gained political power. He also wanted to conciliate leaders of the Reichswehr, the official German military who feared and despised the SA—in particular Röhm's ambition to absorb the Reichswehr into the SA under his own leadership. Finally, Hitler used the purge to attack or eliminate critics of his new regime, especially those loyal to Vice-Chancellor Franz von Papen, as well as to settle scores with old enemies.

At least 85 people died during the purge, although the final death toll may have been in the hundreds, and more than a thousand perceived opponents were arrested. Most of the killings were carried out by the Schutzstaffel (SS) and the Gestapo (Geheime Staatspolizei), the regime's secret police. The purge strengthened and consolidated the support of the Reichswehr for Hitler. It also provided a legal grounding for the Nazi regime, as the German courts and cabinet quickly swept aside centuries of legal prohibition against extra-judicial killings to demonstrate their loyalty to the regime.

Before its execution, its planners sometimes referred to it as "Hummingbird" (German:Kolibri), the codeword used to send the execution squads into action on the day of the purge. The codename for the operation appears to have been chosen arbitrarily. The phrase "Night of the Long Knives" in the German language predates the massacre itself and refers generally to acts of vengeance. Germans still use the term "Röhm-Putsch" to describe the murders, the term given to it by the Nazi regime, despite its unproven implication that the murders were necessary to prevent a coup. German authors often use quotation marks or write about the so-called Röhm-Putsch to emphasize this.

Although the German public did not complain much when SA activities were directed againstJews, Communists, and Socialists, by 1934 there was general concern about the level of civic violence for which the "brown shirts" were responsible.

Hitler and the Sturmabteilung (SA) Hitler posing in Nuremberg with SA members in the late 1920s; Hermann Göring is pictured beneath Hitler, wearing his medals. Julius Streicher is to Hitler's right

President Paul von Hindenburg appointed Hitler Chancellor on January 30, 1933. Over the next few months, during the so-called Gleichschaltung, Hitler dispensed with the need for the Reichstag as alegislative body and eliminated all rival political parties in Germany so that by the middle of 1933, the country had become a one-party state under his direction and control.

Hitler did not exercise absolute power, however, despite his swift consolidation of political authority. As chancellor, Hitler did not command the army, which remained under the formal leadership of Hindenburg, a highly respected veteran field marshal, albeit increasingly frail and senile. While many officers were impressed by Hitler's promises of an expanded army, a return to conscription, and a more aggressive foreign policy, the army continued to guard its traditions of independence during the early years of the Nazi regime.

To a lesser extent, the Sturmabteilung (SA), a Nazi paramilitary organisation, remained somewhat autonomous within the party itself. The SA evolved out of the remnants of the Freikorps movement of the post-World War I years. The Freikorps were nationalistic organisations primarily composed of disaffected, disenchanted, and angry German combat veterans founded by the government in January 1919 to deal with the threat of a Communist revolution when it appeared that there were a lack of loyal troops.

A very large number of the Freikorps believed that the November Revolution had betrayed them when Germany was alleged to be on the verge of victory in 1918. Hence, the Freikorps were in opposition to the new Weimar Republic, which was born as a result of the November Revolution, and whose founders were contemptously called "November criminals".

Captain Ernst Röhm of the Reichswehr served as the liaison with the Bavarian Freikorps. Röhm was given the nickname "The Machine Gun King of Bavaria" in the early 1920s, since he was responsible for storing and issuing illegal machine guns to the Bavarian Freikorps units. Röhm left the Reichswehr in 1923 and later became commander of the SA. During the 1920s and 1930s, the SA functioned as a private militia used by Hitler to intimidate rivals and disrupt the meetings of competing political parties, especially those of the Social Democrats and the Communists.

Also known as the "brownshirts" or "stormtroopers", the SA became notorious for their street battles with the Communists. The violent confrontations between the two contributed to the destabilisation of Germany's inter-war experiment with democracy, the Weimar Republic. In June 1932, one of the worst months of political violence, there were more than 400 street battles, resulting in 82 deaths. This destabilisation had been crucial in Hitler's rise to power, however, not least because it convinced many Germans that once Hitler became chancellor, the endemic street violence would end.

Hitler's appointment as chancellor, followed by the suppression of all political parties except the Nazis, did not end the violence of the stormtroopers. Deprived of Communist party meetings to disrupt, the stormtroopers would sometimes run riot in the streets after a night of drinking. They would attack passers-by, and then attack the police who were called to stop them. Complaints of "overbearing and loutish" behaviour by stormtroopers became common by the middle of 1933. The Foreign Office even complained of instances where brownshirts manhandled foreign diplomats. The stormtroopers' behaviour disturbed the German middle classes and other conservative elements in society, such as the army.

Hitler's move would be to strengthen his position with the army by moving against its nemesis, the SA. On July 6, 1933, at a gathering of high-ranking Nazi officials, Hitler declared the success of the National Socialist, or Nazi, brown revolution. Now that the NSDAP had seized the reins of power in Germany, he said, it was time to consolidate its control. Hitler told the gathered officials, "The stream of revolution has been undammed, but it must be channelled into the secure bed of evolution."

Hitler's speech signalled his intention to rein in the SA, whose ranks had grown rapidly in the early 1930s. This would not prove to be simple, however, as the SA made up a large part of Nazism's most devoted followers. The SA traced its dramatic rise in numbers in part to the onset of the Great Depression, when many German citizens lost both their jobs and their faith in traditional institutions.

While Nazism was not exclusively – or even primarily – a working class phenomenon, the SA fulfilled the yearning of many unemployed workers for class solidarity and nationalist fervour. Many stormtroopers believed in the socialist promise of National Socialism and expected the Nazi regime to take more radical economic action, such as breaking up the vast landed estates of the aristocracy. When the Nazi regime did not take such steps, those who expected an economic as well as a political revolution were disillusioned

Conflict between the army and the SA SA leader Ernst Röhm in Bavaria in 1934

No one in the SA spoke more loudly for "a continuation of the German revolution", as one prominent stormtrooper put it, than Röhm. Röhm, as one of the earliest members of the Nazi Party, had participated in the Munich Beer Hall Putsch, an attempt by Hitler to seize power by force in 1923. A combat veteran of World War I, Röhm had recently boasted that he would execute 12 men in retaliation for the killing of any stormtrooper. Röhm saw violence as a means to political ends. He took seriously the socialist promise of National Socialism, and demanded that Hitler and the other party leaders initiate wide-ranging socialist reform in Germany.

Not content solely with the leadership of the SA, Röhm lobbied Hitler to appoint him Minister of Defence, a position held by the conservative General Werner von Blomberg. Although nicknamed the "Rubber Lion" by some of his critics in the army for his devotion to Hitler, Blomberg was not himself a Nazi, and therefore represented a bridge between the army and the party. Blomberg and many of his fellow officers were recruited from the Prussian nobility, and regarded the SA as a plebeian rabble that threatened the army's traditional high status in German society.

If the regular army showed contempt for the masses belonging to the SA, many stormtroopers returned the feeling, seeing the army as insufficiently committed to the National Socialist revolution. Max Heydebreck, a SA leader in Rummelsburg, denounced the army to his fellow brownshirts, telling them, "Some of the officers of the army are swine. Most officers are too old and have to be replaced by young ones. We want to wait till Papa Hindenburg is dead, and then the SA will march against the army."

Despite such hostility between the brownshirts and the regular army, Blomberg and others in the military saw the SA as a source of raw recruits for an enlarged and revitalised army. Röhm, however, wanted to eliminate the generalship of the Prussian aristocracy altogether, using the SA to become the core of a new German military.

Limited by theTreaty of Versailles to one hundred thousand soldiers, army leaders watched anxiously as membership in the SA surpassed three million men by the beginning of 1934. In January 1934, Röhm presented Blomberg with a memorandum demanding that the SA replace the regular army as the nation's ground forces, and that the Reichswehr become a training adjunct to the SA.

In response, Hitler met with Blomberg and the leadership of the SA and SS on February 28, 1934. Under pressure from Hitler, Röhm reluctantly signed a pledge stating that he recognised the supremacy of the Reichswehr over the SA. Hitler announced to those present that the SA would act as an auxiliary to the Reichswehr, not the other way around.

After Hitler and most of the army officers had left, however, Röhm declared that he would not take instructions from "the ridiculous corporal" – a demeaning reference to Hitler. While Hitler did not take immediate action against Röhm for his intemperate outburst, it nonetheless deepened the rift between them.

Growing pressure against the SA Franz von Papen, the conservative vice-chancellor who ran afoul of Hitler after denouncing the regime's failure to rein in the SA in his Marburg speech.

Despite his earlier agreement with Hitler, Röhm still clung to his vision of a new German army with the SA at its core. By early 1934, this vision directly conflicted with Hitler's plan to consolidate power and expand the Reichswehr. Because their plans for the army were mutually exclusive, Röhm's success could only come at Hitler's expense. Moreover it was not just the Reichswehr that viewed the SA as a threat. Several of Hitler's lieutenants feared Röhm's growing power and restlessness, as did Hitler himself. As a result, a political struggle within the party grew, with those closest to Hitler, including Prussian premier Hermann Göring, Propaganda Minister Joseph Goebbels, SS Chief Heinrich Himmler, and Hitler's deputy Rudolf Hess, positioning themselves against Röhm.

While all of these men were veterans of the Nazi movement, only Röhm continued to demonstrate his independence from, rather than his loyalty to, Adolf Hitler. Röhm's contempt for the party's bureaucracy angered Hess. SA violence in Prussia gravely concerned Göring, Minister-President of Prussia. Finally, in the spring of 1934, hearing of the growing rift between Röhm and Hitler over the role of the SA in the Nazi state led the former Chancellor, General Kurt von Schleicher, to start playing politics again.

Schleicher criticized the current Hitler cabinet while some of Schleicher's followers such as General Ferdinand von Bredow and Werner von Alvensleben started passing along lists of a new Hitler Cabinet in which Schleicher would become Vice-Chancellor, Röhm Minister of Defence,Heinrich Brüning Foreign Minister and Gregor Strasser Minister of National Economy. The British historian Sir John Wheeler-Bennett, who knew Schleicher and his circle well, wrote that Bredow displayed a "lack of discretion" that was "terrifying" as he went about showing the list of the proposed cabinet to anyone who was interested. Although Schleicher was in fact unimportant by 1934, increasingly wild rumours that he was scheming with Röhm to reenter the corridors of power helped stoke the sense of crisis.

As a means of isolating Röhm, on April 20, 1934 Göring transferred control of the Prussian political police (Gestapo) to Himmler, who, Göring believed, could be counted on to move against Röhm. Himmler envied the independence and power of the SA, although by this time he and his deputy Reinhard Heydrich had already begun restructuring the SS from a bodyguard formation for Nazi leaders (and a subset of the SA) into its own independent elite corps, one loyal to both himself and Hitler. The loyalty of the SS men would prove useful to both when Hitler finally chose to move against Röhm and the SA.

By May, lists of those to be "liquidated" started to circulate amongst Göring and Himmler's people, who engaged in a trade, adding enemies of one in exchange for sparing friends of the other. At the end of May, two former Chancellors Heinrich Brüning and Kurt von Schleicher received warnings from friends in the Reichswehr that their lives were in danger, and they should leave Germany at once. Brüning fled to the Netherlands while Schleicher dismissed the tip-off as a bad practical joke. By the beginning of June, everything was set, and all that was needed was permission from Hitler.

Demands for Hitler to constrain the SA strengthened. Conservatives in the army, industry, and politics placed Hitler under increasing pressure to reduce the influence of the SA and to move against Röhm. While Röhm's homosexuality did not endear him to conservatives, they were more concerned about his political ambitions. Hitler for his part remained indecisive and uncertain about just what precisely he wanted to do when he left for Venice to meet Benito Mussolini on June 15. Before Hitler left, and at the request of Presidential State Secretary Otto Meißner, Foreign Minister Baron Konstantin von Neurath ordered the German Ambassador to Italy Ulrich von Hassell - without Hitler's knowledge - to ask Mussolini to tell Hitler that the SA was blackening Germany's good name.

Neurath's manoeuvre to put pressure on Hitler paid off, with Mussolini agreeing to the request (Neurath was a former ambassador to Italy, and knew Mussolini well). During the summit in Venice, Mussolini upbraided Hitler for tolerating the violence, hooliganism and homosexuality of the SA, which Mussolini stated were ruining Hitler's good reputation all over the world. Mussolini used the affair occasioned by the murder of Giacomo Matteotti as an example of the kind of trouble unruly followers could cause a dictator. While Mussolini's criticism did not win Hitler over to acting against the SA, it helped push him in that direction

On June 17, 1934, conservative demands for Hitler to act came to a head when Vice-Chancellor Franz von Papen, confidant of the ailing Hindenburg, gave a speech at Marburg University warning of the threat of a "second revolution". Privately, von Papen, a Catholic aristocratwith ties to army and industry, threatened to resign if Hitler did not act. While von Papen's resignation as vice-chancellor would not have threatened Hitler's position, it would have nonetheless been an embarrassing display of independence from a leading conservative.

In response to conservative pressure to constrain Röhm, Hitler left for Neudeck to meet with Hindenburg. Blomberg, who had been meeting with the President, uncharacteristically reproached Hitler for not having moved against Röhm earlier. He then told Hitler that Hindenburg was close to declaring martial law and turning the government over to the Reichswehr if Hitler did not take immediate steps against Röhm and his brownshirts.

Hitler had hesitated for months in moving against Röhm, in part due to Röhm's visibility as the leader of a national militia with millions of members. However, the threat of a declaration of martial law from Hindenburg, the only person in Germany with the authority to potentially depose the Nazi regime, put Hitler under pressure to act. He left Neudeck with the intention of both destroying Röhm and settling scores with old enemies. Both Himmler and Göring welcomed Hitler's decision, since both had much to gain by Röhm's downfall – the independence of the SS for Himmler, and the removal of a rival for the future command of the army for Göring.

In preparation for the purge both Himmler and his deputy Reinhard Heydrich, chief of the SS Security Service, assembled a dossier of manufactured evidence to suggest that Röhm had been paid twelve million marks (EUR 48.3 million as of 2011) by France to overthrow Hitler. Leading officers in the SS were shown falsified evidence on June 24 that Röhm planned to use the SA to launch a plot against the government (Röhm-Putsch). Göring, Himmler, Heydrich, and Victor Lutze (at Hitler's direction) drew up lists of people in and outside the SA to be killed. One of the men Göring recruited to assist him was Willi Lehmann, a Gestapo official and NKVD spy. On June 25, General Werner von Fritsch placed the Reichswehr on the highest level of alert. On June 27, Hitler moved to secure the army's cooperation.

Blomberg andGeneral Walther von Reichenau, the army's liaison to the party, gave it to him by expelling Röhm from the German Officers' League. On June 29, a signed article in Völkischer Beobachter by Blomberg appeared in which Blomberg stated with great fervour that the Reichswehrstood behind Hitler. Hitler felt confident enough in his position to attend a wedding reception in Essen, although he appeared somewhat agitated and preoccupied. From there he called Röhm's adjutant at Bad Wiessee and ordered SA leaders to meet with him on June 30