The only named Primes are Prima, the first Prime, Sentinel, who remembered his ancestry, Bendy-Bus, whose status is unknown, and Optimus, the last of the Primes.
At least by 17,000 BC, ancient beings known as the "Seven Primes," reached the Solar System in their quest to build a Star Harvester, but they discovered the chosen system contained a life-bearing world, and so six of the Primes objected to using the Harvester on the system's sun. The seventh, however, insisted on using the Harvester anyway upon weighing the longevity of his planet and his race against a seemingly meaningless organic world. This Prime quickly turned on his brothers and their creed, waging war against them, with those who agreed with his ideals by his side. After attacking and killing many of his fellow Primes and slaughtering a large number of early humans he was thereafter ever known as "The Fallen." The remaining Primes mounted an attack on their new nemesis and hid the Matrix of Leadership—without which he could not activate the harvester—in a tomb composed of their own bodies on the very planet he sought to destroy, using the last of their energy left from the epic battle to completely seal it. According to Sam Witwicky, who had absorbed the AllSpark, Sentinel Prime led an expedition where it took him fourteen galactic convergences to get an echo of something, seemingly related to the existence of other dimensions where the theory of relativity was not applicable.In the present day, their descendant Optimus Prime perished in battle whilst protecting the human adolescent Sam Witwicky, the chosen vessel of the AllSpark after the Cube's physical destruction. With the seemingly confusing knowledge of an advanced alien civilization in his mind, Sam and his companions set out to find the Matrix of Leadership after learning it might be the only thing that could resurrect Optimus—the last of the Primes—who was the only being who could defeat "The Fallen". Travelling to Petra in Jordan, Sam discovered the Tomb of the Primes hidden within, quickly discovering the small Matrix. His hopes were soon dampened however, when the artifact crumbled into dust upon it being moved. Nevertheless, he held onto his faith and gathered up the dust in a tattered sock, intending to revive Optimus with it in any way feasible.