Russia and Belarus are behind the sudden revival of an obscure historical conspiracy theory that challenges the foundations of Lithuania’s nationhood, according to the leader of the Belarusian opposition.

There are concerns that the suspected propaganda campaign might furnish President Putin with a specious argument for a military incursion, along similar lines to his notorious essay on the “unity” of Russia and Ukraine.

Sviatlana Tsikhanouskaya, the figurehead of the Belarusian democratic movement, said the dictatorial regimes in Moscow and Minsk had begun whipping up a long-dormant fringe notion that the medieval Lithuanian empire had actually been Slavic, and so large parts of Lithuania belonged to Belarus.

“It was very marginal in Belarusian society. Nobody ever discussed this,” she said. “But they are artificially promoting this idea, trying to sow this perception among Lithuanians that Belarusians are a threat to them. And it really works.”

Until 2020, Tsikhanouskaya, a 43-year-old former English teacher, was a stay-at-home mother whose husband, Sergei Tikhanovsky, abruptly became a prominent protest leader and challenged Alexander Lukashenko, the Belarusian president and close ally of Putin, at the ballot box.

After Tikhanovsky was arrested, his wife ran as an “accidental candidate” in his stead and declared victory. Various entities including Lithuania and the European parliament recognised her as the true president or president-elect of Belarus.

Portraits of freed Belarusian opposition leader Siarhei Tsikhanouski and his wife Svetlana Tsikhanouskaya.

Sergei Tikhanovsky, soon after his release from prison, with his wife Sviatlana Tsikhanouskaya

TADAS KAZAKEVICIUS FOR THE TIMES

However, the official result was heavily rigged in Lukashenko’s favour and his regime forced her into exile across the border in Vilnius, the Lithuanian capital.

Tsikhanouskaya said that she, her family and her colleagues lived under “huge threat” and the Lukashenko regime had hired members of the Wagner group, an infamous Russian mercenary firm, for “acts of aggression against opponents outside [Belarus]”.

“If you think about this, you can lose your mind,” she said.

Russian President Vladimir Putin and Belarus President Alexander Lukashenko smile during a meeting.

Putin, left, and Lukashenko are close allies

DMITRY ASTAKHOV/AP

Over the past few months Lukashenko has made a series of seemingly conciliatory gestures towards the West in an apparent effort to ease the sanctions on his country, including warning Poland that Russian drones were approaching its airspace in September.

He also released about 123 of the 1,500 or so political prisoners in his regime’s jails, including Tikhanovsky, 47, and the well-known activist Maria Kolesnikova, 43.

Tsikhanouskaya said her husband was seeking to return to front-line politics but like many of the detainees he had been “traumatised” by his ordeal in prison.

Nato chief: Europe must prepare for war with Russia

“All these memories, all these injuries, will never be fully healed,” she said. “My husband spends a lot of time with the children, the time he lost. He’s trying to absorb all the information from the five years [of his detention]. Of course he wants to serve the interests of Belarus … [but] sometimes I feel like I’ve got a third baby who needs care and love.”

In January, Tsikhanouskaya moved her office from Vilnius to Warsaw, partly because of concerns that the Belarusian KGB intelligence agency was stepping up its activities against her, and partly because of friction with the Lithuanian government.

One of the biggest sources of tensions is the long and fraught history between the neighbouring nations, whose efforts to assert their national identity frequently run into conflict. Recently, both Tsikhanouskaya and the Lithuanian security services have been alarmed by what seems to be a co-ordinated campaign to weaponise a controversy drawn from the high Middle Ages, known as Litvinism.

From the 13th to the 14th centuries, pagan Lithuanian military leaders such as Mindaugas and Gediminas conquered an enormous tract of eastern Europe that stretched more than 800 miles to the coast of the Black Sea in what is now Ukraine.

In its day, the grand duchy of Lithuania was the continent’s largest state. A Lithuanian warrior elite ruled over a largely Slavic and Orthodox population until the empire was gradually welded to the Catholic kingdom of Poland.

Illustration of the coronation of Mendog (Mindaugas), King of Lithuania, with the King kneeling before a bishop, surrounded by armed soldiers and attendants.

Coronation of Mindaugas, King of Lithuania, 1252

ALAMY

As the region’s borders were rapidly and chaotically redrawn after the First World War, however, Belarusian scholars started promoting various notions that the state had had a predominantly or even wholly Slavic character.

The most extreme form of this idea held that the grand duchy had been forged in modern-day Belarus and that the medieval Lithuanians had been little more than a peripheral confederation of “Samogitian” tribes. That has led to assertions that Belarus has a historically rightful claim on much of Lithuania’s territory, including Vilnius.

For a little over a century, this radical school of Litvinist thought remained a fringe phenomenon even within Belarus itself, disowned by the regime of Alexander Lukashenko, the country’s post-Cold War dictator.

Now, though, Lithuanian officials warn that it is being revived in social media posts, maps, emails to politicians and Belarusian regime rhetoric as a tool of information warfare.

Tsikhanouskaya said she had been so alarmed by the spike in propaganda that her movement had organised a conference on Litvinism to demonstrate that it was an empty narrative.

For now, the chief concern is that the campaign will polarise Lithuanian society and turn public opinion against the country’s 50,000 Belarusians. There are also deeper worries that in the long run Putin could seize on it as part of his broader programme of Slavic revanchism, particularly as he is steadily reducing Belarus to a vassal state.

Francis Young, an expert on medieval Lithuania and secretary of the British-Lithuanian Society, said the Belarusian nationalist ideology was in some ways an awkward fit with Putin’s own notions of Russian supremacy in the Slavic world, but could easily be twisted to suit his purposes.

“I wouldn’t rule it out, given the nature of Russian propaganda,” he said. “Western scholars and western governments particularly aren’t interested enough in the deep history of these nations, whereas the Russians have twisted and corrupted yet deep historical memory.”

Young said radical Litvinism was a distortion of history and the Slavic principalities had been incontrovertibly subordinate to an ethnically and linguistically Lithuanian ruling class.

But he said the idea had gathered momentum in recent years to the point where other western scholars had begun to ask him about it.

“My own suspicion is that rather like Putin, Lukashenko is not so much an ideologue as an agent of chaos,” he said. “Especially when it comes to dealing with Lithuania, the ideology is neither here nor there in the asymmetric warfare and use of anything that comes to hand to cause trouble,” he said.