The details of the Holocaust against Jews are well documented, but the Nazi treatment of the Roma is much less familiar. At the Nuremberg trials treatment of the Roma was not specifically prosecuted. Nor are there precise statistics about the number of Roma killed, estimates vary between 250,000 and 500,000, but proportionately they suffered greater losses than any other group except Jews.

The Wiener Holocaust Library in London holds the oldest Holocaust archive in Britain concerning the Nazi era. The library is performing a valuable service by holding its current exhibition, titled “Forgotten Victims: The Nazi genocide of the Roma and Sinti.” Though the treatment by the Nazis of the Roma was not as systematic as that against the Jews, and started later, it was a genocide, taking similar forms as the Holocaust. Indeed, one poignant reminder of this is the photo displayed of a handsome Roma woman with the Auschwitz tattoo number on her arm.

The Roma and related group Sinti descend from an Indo-Aryan group originally coming from northwest India and dispersed throughout the world. In general, Sinti were located in western and central Europe, while Roma were in south and southeastern Europe.

There has never been an accurate counting of the past or present number of the Roma population, but some estimates suggest the present number is about 3.5 million, with Bulgaria having 10%, and North Macedonia and Slovakia 9% each. In the past, the U.S. apparently absorbed about a million.

The Roma are a distinct ethnic and cultural group, sharing a family of several dialects of a language, and some of them at times living a nomadic mode of life. They are popularly known as Gypsies, a word (Zigeuner) deriving from “untouchables.” That life of Gypsies has been displayed in Western culture, in Carmen by Prosper Merimee and by Bizet, in Shakespeare’s A Midsummer Nights’ Dream, by Esmerelda in Victor Hugo’s The Hunchback of Notre-Dame, and by Van Gogh’s painting The Caravans. Probably the most well-known non-fictional Roma is Django Reinhardt, the legendary Belgian jazz guitarist, co-founder of the Quintet of the Hot Club of France. But other celebrities are said to have a Roma inheritance including Tracey Ullman, the British-American actress, Bob Hoskins, the British actor, Yul Brynner, and perhaps even Charlie Chaplin and Michael Caine.

Initially for any official action against them there was the question of identification. Jews could be more easily identified for the Nazis because of the lists and records available by Jewish committees. However, there was and is not similar documentation of who was a Roma. This made the Nazi regime resort to an individual named Robert Ritter, a “racial scientist,” who tried to identify the Roma by racial type, and thus establish a register of almost all Roma in Germany.

The Roma have long suffered historic persecution and forced assimilation. But that persecution was sporadic and at random. Germany, even before the Nazis, prepared for action against Roma. An office was set up in 1899 in Germany to fight the “gypsy menace.” In 1929, a law held that all Roma in Germany had to register with the authorities. It was the Nazi regime that passed laws for the protection of German “blood and honor,” which aimed at discrimination against the Roma people. Like the Jews, the Roma were considered a racially inferior, and some were sterilized as “mental defectives.” The Nuremberg Laws of 1935 were amended to apply to them as well as to Jews, with consequent loss of citizenship, violence, and persecution, and they were classified as “asocial” persons.

In 1933, a German plan to sink ships containing 30,000 Roma in the Atlantic Ocean was proposed but abandoned. In July 1936 the first concentration camp for Roma was set up at Matzahn, outside Berlin. Others followed in Lackenbach and Salzburg. Lackenbach was the largest camp for Roma, holding up to 2,000, an internment and forced labor camp and deportation point. Salzburg was a forced-labor camp and also preparatory for deportation. Roma from Germany and German occupied territory were the first to be deported to other places including Jewish ghettoes. Adolf Eichmann indicated that carloads of Gypsies were attached to the train transport of Jews. Heinrich Himmler, who in 1938 set up an office to “fight the Gypsy (Roma) menace,” on December 16, 1942 decreed that all Gypsies were to be sent to Auschwitz, but they were also sent to other places. Himmler in 1944 authorized their extermination.

Mass internment in camps for the Roma and Sinti were organized by local German police. The first roundup of Roma was in June 1938. Roma were sent to Lodz, the second largest ghetto after the Warsaw ghetto, in November 1941 where conditions were appalling, and where many died from the typhus epidemic.

Roma were deported, sent from Germany to concentration camps in Poland, Yugoslavia, Bohemia, and Moravia, and eventually to gas chambers. In the concentration camps, the Sinti were forced to wear a black (asocial) or brown triangle. In Auschwitz, Roma were put in a special camp, the gypsy camp, where they were subjected to experiments by Josef Mengele. On August 2, 1944 the special gypsy camp was closed, and all the Roma were gassed in Auschwitz in one night.

This persecution of Roma was not limited to Nazi Germany, but occurred also in Croatia and Hungary in 1944, and other countries who collaborated with the Nazis. In the Netherlands, the occupation authorities interned and later deported its Roma population. The French Vichy regime detained more than 6,000 Roma in the 31 camps in France, mainly at Montreuill-Bellay, where over 2,000 were held under the surveillance of the French police. President Francois Hollande confessed in October 2016 that France had broad responsibility for the internment of thousands of Roma by the Vichy regime.

A secret document signed by Himmler in March 1944 in Nazi bureaucratic language reveals the genocide reality. Prohibitions against Jews and Gypsies, he wrote, were no longer necessary because of the “accomplished evacuation and isolation” by the secret police and intelligence authorities. Roma and Jews had been removed from the Reich. In December 1942, Himmler had ordered the deportation of all Roma from the German Reich. More than 23,000 Roma and Sinti were murdered at Auschwitz, plus killings by Wehrmacht units and death squads. Croatia killed 25,000 Roma, almost the whole population, and had a major concentration camp at Jasenovac, the “Auschwitz of the Balkans,” run by the Croatian military and secret police, not the Nazis. Photos show Serbian gendarmes taking Roma to their execution. Bulgaria wanted to solve the gypsy problem, for them non-native Europeans, by putting them in reservations.

Postwar Germany at first refused to recognize treatment of Roma as genocide committed for racial reasons, but rather spoke of their social and criminal behavior. Only in 1979 did West Germany identify the Nazi persecution of Roma as racially motivated, and began providing compensation for their suffering, and in 1982 acknowledged that Roma and Sinti had been victims of racial persecution by the Nazis.

In Europe today there is no political lobby concerned with Roma welfare. The Wiener exhibition in London may change this. Already signs of change have appeared. In 2011, Poland officially adopted August 2 as the day to commemorate the memory of the 2,897 Roma killed in that one night in 1944 in Auschwitz. Earlier, a federal court in Germany in 1956 held that the deportations of Roma had not been for racial reasons, but a pre-emptive criminal measure. However, in 1985 the German legislature endorsed an apology for genocide committed by the previous regime. On October 2012, a memorial was held in Germany at which Chancellor Angela Merkel spoke. The monument was designed by an Israeli artist, Dani Karavan, and is located near the Reichstag and memorials for the Holocaust.