Had it been possible to discuss these matters some solution might have been reached. Yet even in 2015, at the height of the migration crisis, it was speech and thought that was constricted. At the peak of the crisis in September 2015 Chancellor Merkel of Germany asked the Facebook CEO, Mark Zuckerberg, what could be done to stop European citizens writing criticisms of her migration policy on Facebook. ‘Are you working on this?’ she asked him. He assured her that he was.² In fact the criticism, thought and discussion ought to have been boundless. Looking back, it is remarkable how restricted we made our discussion even whilst we opened our home to the world. A thousand years ago the peoples of Genoa and Florence were not as intermingled as they now are, but today they are all recognisably Italian and tribal differences have tended to lessen rather than grow with time. The current thinking appears to be that at some stage in the years ahead the peoples of Eritrea and Afghanistan too will be intermingled within Europe as the Genoans and Florentines are now melded into Italy. The skin colour of individuals from Eritrea and Afghanistan may be different, their ethnic origins may be from further afield, but Europe will still be Europe and its people will continue to mingle in the spirit of Voltaire and St Paul, Dante, Goethe and Bach.

As with so many popular delusions there is something in this. The nature of Europe has always shifted and – as trading cities like Venice show – has included a grand and uncommon receptiveness to foreign ideas and influence. From the Ancient Greeks and Romans onwards the peoples of Europe sent out ships to scour the world and report back on what they found. Rarely, if ever, did the rest of the world return their curiosity in kind, but nevertheless the ships went out and returned with tales and discoveries that melded into the air of Europe. The receptivity was prodigious: it was not, however, boundless.

The question of where the boundaries of the culture lay is endlessly argued over by anthropologists and cannot be solved. But there were boundaries. Europe was never, for instance, a continent of Islam. Yet the awareness that our culture is constantly, subtly changing has deep European roots. The philosophers of Ancient Greece understood the conundrum, summing it up most famously in the paradox of the Ship of Theseus. As recorded in Plutarch, the ship in which Theseus had sailed had been preserved by the Athenians who put in new timber when parts of the ship decayed. Yet was this not still the ship of Theseus even when it consisted of none of the materials in which he had sailed?

We know that the Greeks today are not the same people as the Ancient Greeks. We know that the English are not the same today as they were a millennia ago, nor the French the French. And yet they are recognisably Greek, English and French and all are European. In these and other identities we recognise a degree of cultural succession: a tradition that remains with certain qualities (positive as well as negative), customs and behaviours. We recognise the great movements of the Normans, Franks and Gauls brought about great changes. And we know from history that some movements affect a culture relatively little in the long term whereas others can change it irrevocably. The problem comes not with an acceptance of change, but with the knowledge that when those changes come too fast or are too different we become something else – including something we may never have wanted to be.