Brand names these days are a mark that suggests a particular product quality to be expected, given that it is made from the same people. How long have humans been doing this?
Interesting example: the workshop of Agathangelus the bronzesmith of Antioch, which made extremely high quality precision bronze instruments, are found all across the Roman Empire, even to London. It was even well known enough that there are fake Agathangelus instruments.
hi! you may be interested in these previous posts
and a few later examples in here
The Ulfberht swords from Viking Age Scandinavia represent one example. These swords were made by someone who was extremely skilled and was an innovator of sorts. The swords were especially strong and yet flexible enough to bend instead of break. They were this way due to a large amount of carbon in the steel. The craftsman inscribed "Ulfberht" onto the base as his own "trademark", you could say. These swords would have been highly, highly prized. Breaking an opponent's sword was a common tactic of fighting at the time and was big trouble if it happened to you. These swords would have been much, much more resistant to breaking than normal swords of the time.
Imitations (of lower quality) were also widespread, and may have been even more prevalent than real "Ulfberht" swords.
A relatively recent article on them: http://jenny-rita.org/Annestamanus.pdf
Also, a modern swordmaker attempted to recreate an Ulfberht sword using all of the same traditional methods...well, almost all of them. He uses a less risky approach when it comes to tempering the sword. This video is very informative: