Italo-German Split
The Italo-German Split was a major diplomatic event in the TNO canon that led to the end of the Rome-Berlin Axis, and the formation of the Triumvirate.
Background
After the end of the Second World War, the Italian Empire and the Greater Germanic Reich's ideological differences on interpretations of fascist ideology began to present themselves in diplomatic disputes. Italy, considered the 'lesser' partner in the relationship, felt as if it was being made to be no less than an extension of Germany's will. Further disputes over border lines in the Balkans, particularly between Hungary and Romania, significantly strained diplomatic relations between Rome and Germania, who had dissenting views over the partitioning of Transylvania.
Additionally, Germania also began to pressure Spain with the Atlantropa plan, an initiative to dam off the Mediterranean sea, which caused significant agitation with the Italian, Spanish, and Turkish economies, who all relied on the Mediterranean to conduct trade. This displeasure weakened the relationship between the members of the Axis, and Italy would respond by beginning to defy German plans for domination, such as resettling Jews in the Levant instead of deporting them.
It was the discovery of German plans to invade Switzerland that would cause tensions to boil over between the powers. Italy viewed this as an attack on the Italian sphere of influence and a defiance of long-standing neutrality. In May of 1952, Benito Mussolini would make a live address is Rome, controversially saying:
"[Germany] has disrespected not only the people of Italy, but all the peoples of Europe who once followed them to victory. If Adolf Hitler cannot remember who his friends are, then surely he must not recall that he will only make enemies through this. If Hitler believes that Italy is a subservient extension of their empire - such as their pithy Reichskommissariats - then they must be reminded that Italy, and all the peoples of Europe living beyond the clutches of his misanthropic Nazism, stand against him!"
The following day, Hitler would reply with a televised address denouncing Mussolini, culminating in denouncing him as a traitor to fascism:
"He [Mussolini] - who fed off German might, German power, German material, German support - now dares to turn and denounce us? He is a coward and a traitor! How can a man who invented fascism so deeply misunderstand the principles he himself authored? Why, because he is not a fascist at all-- but a communist wearing the rags of fascism in disguise!"
Following this insult, Mussolini would withdraw ambassadors from Germania and inform Martin Bormann that he would no longer communicate with Adolf Hitler directly. In response, Adolf Hitler would revoke the treaty of Italian-German friendship that created the Axis, and thus dissolving the pact.
The dissolution of the Axis had adverse effects on Romanian-Hungarian relations and would be one of the main contributors to the Transylvanian War. It also led to the creation of both the Einheitspakt and the Triumvirate thereafter; Italy itself aligning itself with Spain (soon to be the Iberian Union) and Turkey in an axis of resistance to the perceived German threat.
Notably, this Italian action is perceived as having saved Switzerland from annexation despite the significant number of ethnic Germans living within its cantons.