Takagi's proof of the main results of Class Field Theory during WWI is a fascinating example, where a key role is played by Strasbourg leaving Germany and German mathematicians banned from traveling there. Here's a summary taken from my undergrad thesis, the sources are listed on the top of page 46 if you want to read more.

Takagi worked on the main results of class field theory in Japan during the war in seclusion from his German colleagues and was so shocked by the generality of his results that he doubted there validity for quite some time...

 

Although Takagi had already published his important class field theory paper in 1920, his results were not yet well known partly because of disruptions caused by the war. In particular Takagi presented his main papers in 1920 in Strasborg which changed hands after the war, and so the German mathematicians were not allowed to attend. It was only when Siegel persuaded Artin to read these papers in 1922 that Takagi’s results became generally known. The results of Artin’s investigations prompted by his reading of Takagi’s paper is the subject of the second chapter and so the rest of the story of class field theory will have to wait until then.

Takagi's proof of the main results of Class Field Theory during WWI is a fascinating example, where a key role is played by Strasbourg leaving Germany and German mathematicians banned from traveling there. Here's a summary taken from my undergrad thesis, the sources are listed on the top of page 46 if you want to read more.

Takagi worked on the main results of class field theory in Japan during the war in seclusion from his German colleagues and was so shocked by the generality of his results that he doubted there validity for quite some time...

Although Takagi had already published his important class field theory paper in 1920, his results were not yet well known partly because of disruptions caused by the war. In particular Takagi presented his main papers in 1920 in Strasborg which changed hands after the war, and so the German mathematicians were not allowed to attend. It was only when Siegel persuaded Artin to read these papers in 1922 that Takagi’s results became generally known. The results of Artin’s investigations prompted by his reading of Takagi’s paper is the subject of the second chapter and so the rest of the story of class field theory will have to wait until then.

Takagi's proof of the main results of Class Field Theory during WWI is a fascinating example, where a key role is played by him not knowing which cities were still in Germany after the war. Here's a summary taken from my undergrad thesis, the sources are listed on the top of page 46 if you want to read more.

Takagi worked on the main results of class field theory in Japan during the war in seclusion from his German colleagues and was so shocked by the generality of his results that he doubted there validity for quite some time...

Although Takagi had already published his important class field theory paper in 1920, his results were not yet well known partly because of disruptions caused by the war. In particular Takagi presented his main papers in 1920 in Strasborg which changed hands after the war, and so the German mathematicians were not allowed to attend. It was only when Siegel persuaded Artin to read these papers in 1922 that Takagi’s results became generally known. The results of Artin’s investigations prompted by his reading of Takagi’s paper is the subject of the second chapter and so the rest of the story of class field theory will have to wait until then.

Takagi's proof of the main results of Class Field Theory during WWI is a fascinating example, where a key role is played by Strasbourg leaving Germany and German mathematicians banned from traveling there. Here's a summary taken from my undergrad thesis, the sources are listed on the top of page 46 if you want to read more.

Takagi worked on the main results of class field theory in Japan during the war in seclusion from his German colleagues and was so shocked by the generality of his results that he doubted there validity for quite some time...

Although Takagi had already published his important class field theory paper in 1920, his results were not yet well known partly because of disruptions caused by the war. In particular Takagi presented his main papers in 1920 in Strasborg which changed hands after the war, and so the German mathematicians were not allowed to attend. It was only when Siegel persuaded Artin to read these papers in 1922 that Takagi’s results became generally known. The results of Artin’s investigations prompted by his reading of Takagi’s paper is the subject of the second chapter and so the rest of the story of class field theory will have to wait until then.