By Tom Hagler
BBC News, Herzogenaurach, Germany
The German town of Herzogenaurach has been split in half, thanks to a 60-year-old family feud.
In Herzogenaurach, allegiances are still important
Each side has its own bakers, butchers, bars and even schools.
What is equally remarkable in this small, southern German town is that the feud also led to the creation of two famous companies - Puma and Adidas - and, as a result, the birth of the modern sportswear industry.
"It's quite a crazy story because in this little town, Herzogenaurach, a cobblestoned medieval town, you have two of the world's biggest sports companies," says Barbara Smit.
"One on each side of the little river that runs through it."
Mrs Smit is just one of many authors attracted to the story of Rudolf and Adolf Dassler, the feuding brothers who wanted to make the world's first lightweight, but durable, sports shoe.
"They started off together in the 1920s in their mother's wash-room, but they had contrasting characters. One of them was a little bit more ebullient and back-slapping and loudmouth than the other and so they complemented each other well," says Mrs Smit.
"But during the war, these differences had turned into very large arguments also because of the fact that one of the brothers appeared to be much closer to the Nazi cause than the other."
The result was that the brothers never spoke again.
Rudolf, or Rudi, set up his rival firm, Puma, on one side of the river; Adolf, or Adi, stayed on the hill and shortened his name to form Adidas.
The town was split down the middle too. There were questions of personal loyalty, of politics, but also, this was post-war Germany. Jobs were scarce and the brothers ran the only successful businesses in town.
"It was kind of a real war in that Herzogenaurach town was split," says Frank Dassler.
"There was an Adidas butcher and a Puma butcher. If there was a chance to avoid being in the same class as another Adidas person, from the Puma perspective, then we certainly tried to avoid this. Certainly, the restaurants were split, so there was a typical Adidas hotel or Adidas restaurant and the other guys didn't want to go there."
Frank Dassler should know. He is the grandson of Rudolf Dassler, of Puma.
He is also the man who more than anyone has helped build a bridge between the two warring factions. He broke the town's taboo and has worked for both of them.
"I had been working for Puma for 10 years during the 1980s and then I was asked by Herbert Heiner, the CEO of Adidas if I would be in the new general council. I said you must be crazy to hire a Puma Dassler to go to the Adidas company and he said well, the times have changed and it was 15 years ago.
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"It was always my dream to get back to the industry, but not some of the locals, they were shocked.
"There was a big newspaper article in the two local newspapers saying that it was a kind of betrayal to the old Puma history and some of my family members from the Puma side have been a little bit, let's say, angry with me."
The town remains obsessed with the brothers' story. In fact, a whole museum has been dedicated to them.
The museum traces their history from their fledgling business in 1924 in their mother's laundry room.
It has the bicycle-powered machine which they would pedal to motor a cutter to trim the leather.
As it was just after World War I, they used whatever they could scavenge - including parachutes and army helmets.
Even in death, Rudi and Adi were not reconciled. At the local cemetery, their graves are about as far apart as you can get.
But their legacy means, in sporting parlance, that Herzogenaurach punches above its weight. Of all the teams playing in this World Cup, for example, more than half will be wearing Adidas or Puma kit.