How It All Began
According to Wikipedia, Transformers is a media franchise produced by American toy company Hasbro and Japanese toy company Takara Tomy.
Initially a line of transforming toys rebranded from Takara's Diaclone and Microman toylines, the franchise began in 1984 with the Transformers toy line.
The story focuses on 2 factions of transforming alien robots called Autobots and the Decepticons in an endless battles for victory.
In its decades-long history, the franchise has expanded to encompass comic books, animation, video games and films.
Generation 1 or G1 covers both the original animated television series The Transformers and the comic book series of the same name, which are further divided into Japanese and British spin-offs respectively.
Sequels followed, such as the Generation 2 comic book and Beast Wars TV series, which became its own mini-universe.
Generation 1 characters underwent two reboots with Dreamwave in 2001 and IDW Publishing in 2005, also as a remastered series.
There have been other incarnations of the story based on different toy lines during and after the 20th-Century.
The first was the Robots in Disguise series, followed by 3 shows Armada, Energon and Cybertron.
They constitute a single universe called the Unicron Trilogy.
For movies, the first animated feature Transformers The Movie was released in 1986 between Seasons 2 and 3 while the live-action version was finally released in 2007, followed by sequels in 2009, 2011 and 2014.
The Transformers – Animated Series merged concepts from the G1 story-arc, the 2007 live-action film and the Unicron Trilogy.
Transformers – Prime previously aired on The Hub.
Although initially a separate and competing franchise started in 1983, Tonka's Gobots became the intellectual property of Hasbro after their buyout of Tonka in 1991.
Subsequently, the universe depicted in the animated series Challenge Of The Gobots and follow-up film GoBots: Battle Of The Rock Lords was retroactively established as an alternate universe within the Transformers franchise.
For more information on the history of Transformers, check out this video: