– In the Baltics, there may be no war on Christmas, but there's a pretty prickly one over the tree.

For six successive seasons, Riga and Tallinn — the capitals of Latvia and Estonia — have waged a feud over which was the site of the world's first decorated Christmas tree. Riga says it was first, in 1510. Tallinn claims a much earlier event, in 1441.

More than civic pride is at stake. Christmas-themed travel has become extremely lucrative, especially in the ice-choked north, where there are no swaying palms to lure the winter-weary.

And this year, the rivalry has taken on an added urgency and a darker tinge.

Simmering tensions between Russia and NATO and the faltering Russian economy have squeezed tourist traffic from what had been a prime source of vacationers. And the deadly attack on Berlin's Christmas market this week has raised fears that holiday markets, in general, may see fewer customers for their hot spiced wine and sugary treats.

The Christmas tree spat began in 2010, when Latvians started an advertising campaign that claimed that Riga was the first, citing 1510 as the year when a mysterious and rambunctious medieval brotherhood known as the House of the Black Heads paraded through Riga carrying a constructed replica of a tree. They decorated it with fruits and candles, danced around it and then, a few days later, burned it to the ground.

Hold on a second, responded the Estonians. They produced evidence that they claim showed that a similar festival had taken place at yet another lodge of the Black Heads, this one in Tallinn in 1441.

And their festival, Estonians claim, involved a real tree. In fact, said historian Juri Kuuskemaa, "we can be sure it was a spruce."

Riga's mayor, Nils Usakovs, countered that claim by saying that the Estonians employ post-truth tactics when it comes to the invention of the Christmas tree.

It's an unusual war, fought with ornaments and historians.

Whizzing round the capital the week before Christmas, Usakovs has taken on the work ethic of an elf. At the foot of a former landfill site that is being converted into a miniature ski resort, Usakovs lit his 48th Christmas tree of the season.

He said the Christmas tree conflict, in reality, had reached a bit of a historical stalemate, as there was not enough contextual evidence to say for certain which city came first. But he doesn't care.

"Any time they say they were first, they have to mention also our city," he said. "Tourists from Germany or Belgium or Russia don't care for historical truth; they care about cities with fancy Christmas trees, fancy Christmas markets. And when they read that there is also this battle between Tallinn and Riga — it's fun!"

Nearly 200 miles north, in Tallinn, the chairman of the Estonian Parliament's defense committee, Hannes Hanso, stood beside the official parliamentary tree and declared that he took a policy of total nonrecognition when it came to Riga's claims.

"I didn't know Latvia had any claim to the first Christmas tree," he said with mock incredulity.

Not everyone is in the Christmas spirit. Gustavs Strenga, an archivist and historian at the National Library of Latvia, said that both Riga and Tallinn were guilty of making creative leaps with their historical interpretations.

Actually, he said, those tree-themed celebrations by the Black Heads had nothing to do with Christmas and were connected to other festivities the brotherhood celebrated.

Looking down at his coffee cup, Strenga admitted that his skeptical position had not gone down well in Latvia.

"I've been called the Grinch," he said.