The history of post-war immigration to West Germany is generally thought to have begun in 1955, when the first Gastarbeiter, or guest workers, arrived to fill labour shortages. But even before that, the Federal Republic had a small but significant population of non-European immigrants, including several thousand Armenians, Caucasians, Kazakhs, Kyrgyz, Tatars and Uzbeks who had fought with the Germans against the Soviet Union during World War II and sought refuge in Germany after it ended. It is with the previously almost completely unknown story of this population – in a sense, the West German equivalent of the West Indian servicemen who settled in Britain after the war – that Ian Johnson’s superb book A Mosque in Munich begins.

During the war, these Soviet minorities – most of them Muslims – had been organised into an infantry battalion that was subsequently taken over by the SS and turned into a new unit, the East Turkestani Armed Formation, which helped put down the Warsaw uprising in 1944. Other Soviet minorities also fought alongside the Germans, but it seems the Nazis had particular faith in Muslims. “I consider only the Mohammedans to be safe”, Hitler had told his generals. The key figure in organising the Soviet minorities was a German orientalist named Gerhard von Mende, who worked as an official in Nazi ideologue Alfred Rosenberg’s Ministry for the Occupied Eastern Territories, or Ostministerium.

In the first of a series of twists in this remarkable story, Johnson, a reporter for the Wall Street Journal who won a Pulitzer Prize in 2001 for his coverage of the Falun Gong in China, shows how von Mende in effect recreated the Ostministerium after the war. With the help of West German intelligence, he brought back old colleagues – many of them Baltic Germans like him who had a visceral hatred for the Soviet Union – and also hired carefully selected representatives of the Soviet minorities. One of them was Nurredin Namangani, an Uzbek who had been the imam of the SS unit and won the Iron Cross during the war, who was appointed as the group’s leader. Together they began to make plans to build the eponymous mosque in Munich as a place of worship for the men.

In the 1950s, the Americans also began to see the potential of this cohort of Soviet exiles. A CIA vehicle called the American Committee for Liberation – Amcomlib for short – which ran radio stations that broadcast into Eastern Europe but also undertook covert operations, saw the Soviet minorities as potential agents who could help win support among their populations. As Johnson shows, they used much the same approach as the Nazis – in particular, by using what President Eisenhower called “the spiritual factor” as a weapon against the godless Soviet Union. That model would later be applied on a much greater scale in Afghanistan in the 1980s after the Soviet invasion in 1979, with spectacular success but ultimately disastrous consequences.

Perhaps the most interesting and important character in this story that skilfully links the apparently disparate histories of Nazism, the Cold War and Islamism is Said Ramadan. Ramadan had been the right-hand man, and son-in-law, of Hassan al-Banna, who had created the Muslim Brotherhood in Egypt in 1928 and was assassinated in 1949. The Brotherhood was anti-communist, anti-imperialist and anti-Semitic (al-Banna himself admired the Nazis), but its ultimate aim was to establish sharia law throughout the Muslim world. As its slogan put it: “The Koran is our constitution, jihad is our war, martyrdom is our desire.”

Ramadan arrived in West Germany in 1956 after being forced to leave President Nasser’s Egypt, began a PhD in Cologne and also became involved in the mosque project – apparently at the invitation of Arab students who were members of the Muslim Brotherhood. But, according to Johnson, Ramadan was almost certainly backed by the CIA (though Ramadan’s family, including his son Tariq, himself an influential and controversial Islamic intellectual, denies this). Although the Americans had some reservations about the globetrotting Ramadan – he “seems to be a fascist”, one CIA analyst wrote in a report – they also saw him as a potent ally in their struggle against communism.

As a result of their energy, money and political skill, Ramadan and his followers ousted von Mende and the ex-soldiers and took control of the mosque project. The Islamic Centre of Munich was finally opened in 1973. However, Johnson suggests that it was only after the Cold War ended – by which time Said Ramadan had himself been ousted from the group – that its real significance would become apparent. After all, the Islamists’ aim had never been to create a place of worship for the city’s Muslims – in fact, they initially excluded local Turkish guest workers – but to form a base for a political movement that would eventually spread across Europe.

Johnson argues that they succeeded. After 9/11, German authorities attempted to link the mosque to terrorism and the US froze the assets of several key figures within it. But Johnson argues that the real importance of the mosque, which subsequently became the headquarters of the Islamic Community of Germany, is the way it created a network of organisations across the continent (including in Britain) that promoted Islamist ideology. It thus became the European hub of what Gilles Kepel has called the ‘neo-Muslim Brotherhood’ – a more pragmatic version of the original Egyptian political party that operates within the law. In that sense, the story of the mosque in Munich is not just important as a kind of pre-history to American support for the mujahideen in Afghanistan in the 1980s but can also be seen as the birthplace of Islamism in Europe.