Kindly read the last sentence of this paragraph:
"In the 1920s, a German named Adi Dassler created a new sneaker brand that he named after himself: Adidas. His brother, Rudi, later started his own shoe company: Puma. As new athletic shoes were developed, people around the world began to use them for many different sports.
It wasn't until the 1950s, however, that tennis shoes became popular as a fashion statement outside of any connection with athletics."
Now I can understand the meaning of this sentence:
"It wasn't until the 1950s that tennis shoes became popular as a fashion statement outside of any connection with athletics."
It basically means from 1950s onwards tennis shoes were not only atheletic shoes, but they were worn as casual shoes also for any non sport occasion like hanging out with friends or a casual meeting.
Now, if you use 'however' like in the original paragraph, what does 'however' mean here? Does it make the meaning of sentence opposite (i.e., from 1950s they became ONLY atheletic shoes, no more used as casual shoes for non-sport events) to what I understood above?