We do not know if Benjamin of Tudela traded coral or gems. We do not know the name of his parents, or the names of his lovers. Nor do we know the site of his grave. But we know he travelled, for 10 years – some say 14 – and that he wrote. Or rather, he recorded. 

Benjamin was the Jewish Marco Polo. He left Spain around 1160 and returned in 1172. Seeking the blessing of the land of Israel he travelled – by boat, by camel, on foot – the long way round: through Genoa, Rome and Constantinople, across the Holy Land ruled by French speaking Crusaders, and back through Aleppo, Alexandria and Baghdad. 

The Rabbi left us The Book of Travels – and this, for secular historians at least, is a treasure to rival the Zohar. Why? Not only because no 12th century traveller had a keener eye for the cities he visited – his descriptions of Constantinople are the most vivid then written – but because he wrote to record, and to count, the Jews. 

They were silk weavers in Thebes, they were tanners in Constantinople; they were glass workers in Aleppo and Tyre. They were 200 in Rome. They were 7,000 in Mosul. They were a nation almost entirely Mediterranean and Middle Eastern. The Jews of Europe were for Benjamin only a few thousand – and only hearsay. Almost a rumor, spreading east in Northern France and Germany. “They are full of hopes,” wrote Benjamin, “And say: “Be of good spirit, dear brethren, for the salvation of the Lord will be quick, like the twinkling of an eye.”

Reading The Book of Travels one is left with one conclusion. Sephardic and Mizrahi Judaism, rather than a curio, is in the greatest sweep of Jewish history the mainstream. Ashkenazi Judaism was the flickering. Next to non-existent in the early middle ages, ballooning suddenly, only to almost vanish from Europe in less than five centuries.  

None were more aware of this than the Rabbis, when the 15th century Rabbi Mosses Isserles ruled his commentary on the Shulhan Arukh he was enshrining in Krakow specific distinct customs and traditions, what he saw as a branch, not the trunk of Judaism. These rulings – as if for an offshoot – came to define the Ashkenazi rite.

Piecing through texts and cemeteries, historians have estimated the historical Jewish population. As Benjamin travelled in the 12th century over 80 percent of Jews lived in Mediterranean and the Middle East – scholars estimate less than 12 percent were living in Europe. Until the 16th century, after the expulsion from Spain, the majority of Jews lived in Islamic lands – they were Mizrahi or Sephardi. 

The history we know only too well meant the centuries of a Judaism centered in Europe are historically brief. In 1880 nearly 90 per cent of Jews were Europeans. In 1939 about 57 per cent were. Come 1960, still, some 27 per cent of Jews lived in Europe. Today barely 10 per cent of Jews are European. Jews in Europe have fallen from 2m in 1991 to less than 1.4m today. 

We remember why European Judaism collapsed. But why did it boom? Demographic historians explain that Europe entered “a demographic transition” centuries before the Mediterranean and the Middle East. The very basics of sanitation came to the shtetl centuries earlier: clumsy plumbing, rudimentary medicine and basic sanitation – allowed the Ashkenazi mortality rate to fall whilst the fertility rate stayed high. 
  
Historically this lucky plumbing was only to be a flash in the pan. Judaism is now slowly returning to what it always was: a primarily Middle Eastern phenomenon that Benjamin would have recognized better than the shtetl. Today roughly 45 per cent of the world’s Jews in Israel (which has overtaken the United States, where some 40 per cent live). With the Israeli Jewish population booming, with an average of three children per family, and the US Jewish population ageing and declining the majority of the world’s Jews will again be Middle Eastern by 2050.

In Judaism, what was will be, and Europe was but a twinkling of an eye.