A family feud

Quite the story -- I knew the two companies were from the same family but I never heard about the feud. From Neatorama:

Family Feud: Adidas vs. Puma
FOOT SOLDIER
Not long after the end of World War I in 1918, an 18-year-old German soldier named Adolf Dassler returned to his hometown of Herzogenaurach, in northern Bavaria. Shoemaking was the biggest industry in the area, so it was no surprise when he decided to become a cobbler.

Dassler started small, working in an empty laundry shed behind his parents' house. There he constructed his first shoes -- work shoes -- out of leather scraps salvaged from wartime army helmets and other gear. His interest soon turned to athletic footwear. An inveterate tinkerer, he made his first sports shoes for his friends. But as his designs improved, his reputation spread beyond Herzogenaurach, and he soon had more work than he could manage by himself.

In 1923 his boisterous older brother Rudolf joined his business. "Rudi" handled sales while "Adi" made the shoes. In 1924 they formalized their partnership by founding the Dassler Brother Shoe Company. Two years after that, they moved their growing business into a factory on the other side of town.

Some more:

Hitler intended the Olympics to serve as a showcase for the Nazi doctrine of Aryan racial superiority, but all the Dasslers cared about was getting Jesse Owens, the famous African-American track-and-field star, to wear Dassler Brothers shoes in the games. He did, and won four gold medals. Owens' victories gave the company its first international exposure. Soon athletes from all over Europe began making their way to tiny Herzogenaurach whenever they passed through Germany, to get a pair of Dassler Brothers shoes.

A bit more:

As the years passed and Adidas and Puma loomed ever larger over the economy of tiny Herzogenaurach, the entire town was drawn into their feud. Nearly everyone worked at one company or the other (or was related to someone who did), so few people could avoid choosing a side. Dating, even socializing, across company lines was frowned upon. Marrying someone from the other side was out of the question. Herzogenaurach became known as "the town of bent necks," because people looked down to see which shoes people were wearing before engaging them in conversation.

Adidas people bought their bread from bakers who sided with Adidas, bought their meat from Adidas-friendly butchers and drank in Adidas-only beer halls. Puma workers did the same. Which bus a child took to school depended on whose side their parents were on, and so did the gang the kid joined. The rivalry that started soon after birth went all the way to the cemetery: Each side had its own tombstone carvers. And when Adi and Rudi died four years apart in the 1970s, they were buried in opposite corners of Herzogenaurach cemetery, as far apart as possible. They had carried their feud to the end of their lives, and the same was expected of everyone else.

This is just a small excerpt from a much larger article -- amazing story and the feud continued through two generations of children. It also goes into how the corporate culture of both companies failed to recognize the threat of both Nike and Reebok.