Otto Frank was born a Prussian national. From 1866 to 1933, Frankfurt am Main belonged to the Kingdom of Prussia,^[1] which meant that its citizens were assigned Prussian nationality. In 1871, the German Empire was established, but the population retained their separate Prussian, Bavarian, Saxon, etc. nationalities. After 1933, the various states, including Prussia, were brought into line with the Third Reich. The transition from Prussian to German was a consequence of the Gleichschaltungsgesetze (Consolidation Laws) of 31 March and 7 April 1933.^[2] In the Frankfurt population register, Otto Frank's nationality, as well as that of his family and household, is listed as Pr.^[3] His enrolment form at Heidelberg University (1909) lists: Staatsangehörigheit: Preusse.^[4] From February 1934 onwards, all citizens were assigned Deutsche Staatsangehörigkeit (German nationality).^[5] According to the household card in the Amsterdam population register and the foreigner's card in the police archives, both drawn up in the summer of 1933, Otto Frank was German.^[6]

German or stateless?

On 25 November 1941, Otto Frank and his family became stateless citizens overnight,^[7] 

This regulation decreed that all Jews with German nationality living abroad would lose their citizenship.^[8] as a consquence of the Elfte Verordnung zum Reichsbürgergesetz (Eleventh Decree of the Reich Citizenship Law) of 25 November 1941. The Elfte Verordnung was one of a total of thirteen supplementary executive decrees to the Reich Citizenship  Law of 15 September 1935,^[9] one of the so-called "Nuremberg Laws" that robbed German Jews of their civil rights.^[10]  Following the Second World War, the Allied occupying powers repealed Nazi legislation. This caused a lack of consensus about the legal status of pre-war German Jews in the Netherlands: were they now German or stateless? It was not until the summer of 1946 that the Dutch government took the position that ausgebürgerte (expatriated) German Jews were stateless. But in the eyes of the Dutch judiciary, the pre-war German Jewish refugees were now once again German citizens due to the repeal of Nazi legislation by the Allies and were therefore, de facto, “enemy nationals” under Dutch law, which, according to normal procedures, justified an investigation. However, according to the Military Authority (which governed the country during the exceptional state of siege and supervised foreigners and guarded the border until 1 September 1945), they were stateless and the repeal of Nazi legislation only applied to German territory occupied by the Allies. According to the Military Authority, all pre-war German Jews who had an official Dutch residence permit predating 10 May 1940 were therefore granted protection on Dutch soil under Article 4 of the Constitution. It was not until the summer of 1946 that this lack on consensus was resolved, when the government took the position that the ausgebürgerte German Jews were stateless (assuming that they had not engaged in anti-Dutch behaviour during the occupation). Pending the final settlement, they were granted a residence permit.^[11]

As Otto Frank had been legally residing in the Netherlands as a German Jew since before 10 May 1940 and there were no objections to his presence, he was granted a residence permit, which had to be renewed annually, pending a final decision. His foreigner's card lists the dates on which he had his visa renewed, both before and after the Second World War.^[12] There was still the possibility of opting for German nationality. However, Otto Frank wanted to become Dutch and did not make use of this option. On 18 February 1948, he declared in writing that he had not requested the German authorities to retain his German nationality and would not do so.^[13]

Naturalization

As early as the autumn of 1945, Otto Frank had intended to become a naturalised Dutch citizen. According to an overview compiled by Otto Frank entitled “Naturalisation” and according to an entry in his diary from 1946, his citizenship procedure began on 9 February 1946 with the payment of two hundred guilders to the Ministry of Justice. On 14 May 1948, the Royal Commissioner in North Holland advised that Otto Frank's naturalisation should be given priority “in view of the Dutch interest involved.^[14] On 10 March 1949, Otto Frank noted at the end of his overview: “has been added to the Adlerstein list.”^[15] This was a list of twenty people, including Otto Frank, who would be granted Dutch nationality as a group. With its publication in the Staatsblad on 16 December 1949, Otto Frank's naturalisation as a Dutch citizen became a fact.^[16]