Communities should embrace the “sizeable movement” of people with Jewish ancestry who wish to reconnect with their roots, a Euro-Jewish activist urged.

More than a hundred people tuned into a lunchtime talk by David Weis on “Ashkenazi Marranos” – part of a special “spotlight on Europe” track in the Limmud festival programme.

In contrast to an often-repeated scepticism about the future of Jewish life in Europe, he painted a more hopeful picture.

“A lot of people thought there would be one or two generations [after the War] and they’d be gone,” he said. “Now we know they are there to stay.”

The president of Liberal Judaism in Luxembourg, he sits as a representative of his country at the Council of Europe and has been involved with the Limmud Europe Values project.

There had been a renewed interest in Judaism in Western Europe since the 1990s and Jews were more visible. Both among Jews and non-Jews, there was “more interest in the Jewish contribution to global history,” he argued.

While he was not advocating a campaign to proselytise, he said communities needed to be open to people who had Jewish roots.

In order to encourage approaches, he said, “On our internet and facebook pages we have been putting stories of people who have returned to Judaism."

His own community of around 250 includes a Portuguese diplomat who discovered he had Jewish roots. “ We have 10 to 15 people contacting us every year saying ‘I have Jewish roots, what can I do about it?”

While some went on to “completely return” and convert, others wanted just to keep in touch and learn more about their Jewish heritage.

There were “all sorts of reasons that push people to come back,” he said. “But it’s a sizeable movement”.

One reason was a “revenge on history”, a belief that the historical forces that had caused their ancestors to give up Judaism had been “unfair. They want to make things right, it’s really a sense of justice”.

In some cases, people researching their family tree in order to see if they qualified for citizenship of a country found out that they had Jewish ancestors.

Those who returned demonstrated “a positive message” of how strong Jewish identity could be, despite the discrimination and hardships of the past.

“We should remain positive and see how we can build communities that are future-proof,” he said.