Not a historian, but I can tell you that there cannot be an absolute monopoly without government intervention or some kind of limiting force (which is illegal in most countries).

A monopoly means one firm is the only firm to offer a certain good for a market, which means no other firms may offer the same good. In short, no competition. In all cases where there is no or little government intervention, there is competition to some extent, even though a large company might have most of the market shares, one can assume they will never reach 100%, as other firms are allowed to produce the same good.

There is also no such thing as a perfect monopoly. If there is a government-imposed monopoly, there will likely be a black market for the good, which even though it is illegal, will cause competition on the market, which in turn obstructs the definition of a monopoly, which is no competition.

However, theoretically, if one firm somehow was able to control all the raw materials to produce one certain product, a monopoly could be established as no other firms would be able to produce the same product. Nevertheless, there would likely be substitutes on the market (E.G. soy milk vs milk), which means there would be competition to some extent.

An example of a government-imposed monopoly is the Norwegian national liquor store literally translated to "the wine monopoly", which is the only firm allowed to sell alcoholic beverages with a higher alcohol content than 4.75% vol. Due to this, there is a black market established, and in addition to this, consumers pursue other markets (such as the Swedish market) in order to purchase cheaper alcoholic beverages, which causes competition. "The wine monopoly" is not a perfect monopoly, and never will be, unless Norway shuts down its borders like North Korea and somehow logs all alcoholic beverages in the country (which is pretty much impossible).

My point being, there cannot be a perfect monopoly, neither government-imposed nor market-imposed, but one firm may hold a large market share, causing other firms to lose profit. In most cases, however (in a free market), there will be at least two large competitors, such as Coke and Pepsi, or Burger King and McDonalds, in addition to smaller local competitors.

Unfortunately I cannot present an accurate example as I do not know of a situation where one firm has held above 95% of the market shares without government intervention.

TL;DR There cannot be a perfect monopoly, but even an imperfect monopoly is not likely to occur unless there is government intervention.

AT&T is another monopoly that was broken up, then reformed. They owned the rights to build the phone lines, the lines and poles themselves, and for a long time, they were the sole providers of telephones themselves. They also controlled the switchboards and other routing hardware.

There were some smaller companies, but they were very localized, usually to one small city, and had to pay AT&T for access to make calls outside of their area.

Sorry, we don't allow throughout history questions. These tend to produce threads which are collections of trivia, not the in-depth discussions about a particular topic we're looking for. If you have a specific question about a historical event or period or person, please feel free to re-compose your question and submit it again. Alternatively, you may PM /u/caffarelli to have your question considered for an upcoming Tuesday Trivia thread.