Donald Trump has long claimed to be proud of his German ancestry. But the American president might be wise to reconsider.

Christ was one of the Nazi party’s Alter Kämpfer – loyalists who had joined in the party’s pariah years

At the end of last month, the US National Archives published the files of millions of Nazi party members online. The documents had been saved from the Nazi party’s headquarters in Munich in April 1945 by the owner of a local paper mill, who had disobeyed orders to destroy them ahead of the American advance on the city. Instead, he hid them, handing them over to US troops who, in turn, used the files to prosecute former Nazis in the aftermath of the second world war. The US handed the original files to the Federal Archives in Berlin following German reunification in 1989, but kept hold of digital copies.

A dig through the archives has thrown up the Nazi party membership card for a Philipp Christ, born 21 June 1893 in Kallstadt, the Bavarian Palatinate. Philipp Christ was a winemaker and joined the party aged 35 on 1 May 1929 as its 133,667th member. This made him one of the Nazi party’s Alter Kämpfer – ‘old fighters’ – loyalists who had joined in the party’s pariah years.