What kind of a free market liberal society was Germany on the eve of the First World War? Robert Martin, a retired civil servant who had worked in the Ministry of the Interior, earned his keep by assembling detailed information from German tax statistics in his twenty-volume series Yearbook of German Millionaires. The collection included named individuals possessing a fortune worth more than a million marks, also giving their addresses. Since the annual publication was “bought as well as studied with the greatest care by the well-to-do, not only in Germany but in the whole world”, Martin claimed that it was also “the most effective advertisement for the millionaires”. Martin also stated that the 10,000 individuals included in the new edition on the Rhineland (the western centre of heavy industry in Prussia) had been very helpful in improving the quality of the data by voluntarily submitting additional material, making it very likely that its coverage was complete. Even the emperor could be included, although he paid no tax in Prussia: his annual income exceeded the next wealthiest individual by 3 million marks, but he was not the wealthiest millionaire. That spot went to Bertha Krupp, recorded with a fortune of 283 million marks. Luxury and private wealth were apparently popular topics in those days, and nobody seems to have worried that thieves and conmen might also make use of the publication.

Thanks to Thomas Piketty and his team – among whom Fabien Dell assumed responsibility for the German component – we are all now aware that industrialized societies suffered from serious, and in many cases increasing, economic inequality at the end of the nineteenth century. Private wealth reached a level six times the national income around 1910. A fortune of a million marks was 800 times the average income of employees, making the 10,000 millionaires of Martin’s yearbook a much more exclusive group than the 892,000 euro-millionaires in Germany today. Private wealth of a million euros today equals only thirty times the average annual income. However, Bertha Krupp’s wealth in 1913 was 0.56 per cent of national income, while the fortune of the richest Germans today, the BMW-owning family the Quandts, is 0.87 per cent of current German GDP.