Fanta was invented in Nazi Germany having followed a shortage in Coca Cola.

During WW2, the United States established a trade embargo against Nazi Germany, making it difficult to ship Coca Cola syrup to Germany.
Having being a very popular beverage in Germany at the time, the population was outraged at the news, but nothing could have been done about it.

News spread and eventually Max Keith, head of Coca Cola Deutschland, decided to take matters into his own hands.
Instead of creating a new Cola-like beverage, Max tried his own hand in making an entirely new beverage.

Max had a lot of trial and error, especially when it came to making the beverage sweet.
Due to the extreme rationing of sugar at the time, Max had to find other ways to make the drink sweet.
Max eventually ended up using ingredients such as Sugar beets, apple pomace, whey, which was a cheese bioproduct, and a few more.

As for the name, there wasn't any real reason behind it.
Just a bunch of people shouting names that came up their minds, throwing shit at the wall and seeing what sticks.

The newly named beverage, Fanta, absolutely blew up in Germany and, by 1943 (2 years later), around 3 million cases were sold.
Many of the bottles weren't consumed as a drink, but rather as an alternative to sugar in many foods such as soups and stews due to the aforementioned severely rationed sugar.

A few years later Max put the Fanta brand at the disposal of the Dutch Coca Cola, of which he had been appointed as the official caretaker.

Fanta production stopped in 1949 and resumed in 1955 in Naples, Italy, now with the orange formula we all know and love.