Introduction
Whenever one group of people is threatened by another, the faction with the disadvantage will always seek to even the odds. As such, when mankind came to realize the existence of an offshoot of humanity ominously labeled 
Homo superior, people born with mutant abilities against which conventional weapons were of little use, an undeclared arms race began. Against these mutants and their innate powers, mankind would endeavor to enlist its technological prowess – and thus the Sentinels were conceived and constructed.
As with any innovative achievement, humanity’s drive to improve and enhance its creation would result in each successive Sentinel program furthering the automatons’ abilities… and their menace. Unfortunately for many of those who sought to utilize them toward humanity’s defense, they would soon learn first-hand the cautionary maxims of being unable to un-ring a bell or putting the genie back in the bottle. Just as Oppenheimer lamented his role in the splitting of the atom, so too would the Trask family and many of those who followed rue the day they attempted to thwart one enemy of mankind by accidently creating another.
Sentinels Mark I
| Creator: | Dr. Bolivar Trask |
| Appearances: | Uncanny X-Men #minus 1, X-Men (1st series) #14-16 |
| Mark I Sentinels: | considerable strength, speed, durability, computing power, mutant-detecting "computo-meters", concussive blasters, fiery heat rays, stun rays, destructo-beams, micro-electric blasts, and boot-mounted propul-units for flight |
| Master Mold: | four times the size of a standard model, possessing significantly advanced strength, weapon systems, and built in disintegration ray, ionic power source enabled it to create new Sentinels in conjunction with a manned birthing creche, sending charged syntho-particles into the machine which recreated the particles into solid matter using pre-programmed blueprints and data |
The history of the Sentinels starts with Dr. Bolivar Trask, a noted anthropologist from Philadelphia. Both of his children turning out to be mutants, Trask was one of the first to learn of the birth of a new species, Homo superior. Due to his scientific knowledge of mankind's evolution, Trask knew that sooner or later Homo superior and Homo sapiens would fight each other for dominance. He might have well accepted baseline humanity’s fate as becoming extinct, had he not become convinced that mutants posed a great threat not only to others but also themselves. One such mutant was his daughter, Tanya, who couldn't control her powers to phase out of synch with time and became lost in the timestream. Plagued by precognitive visions he didn't fully understand, Larry Trask told his father about the crimes that “evil mutants“ would commit in the future, prompting Bolivar to take action.
After designing a medallion that would negate Larry's abilities as well as suppress his memories of his status as a mutant, Bolivar began to design humanity's defense against the rising threat of mutants. Ironically, his son even helped him in that task. For the next years, Bolivar Trask spent most of his family fortune to design the Sentinels – giant robots charged with the apprehension or elimination of mutants. However, rather than to build each Sentinel by hand, Trask constructed a Master Mold unit first. Based on the Sentinels' blueprints in its databanks, the Master Mold would assist Bolivar in creating more Sentinels as well as coordinate their efforts. [Uncanny X-Men #minus 1]
Eventually, Dr. Trask was ready to launch his Sentinel project and he introduced his creations to the public during a televised debate with Professor Xavier, one of the world's leading experts on genetic mutation. Not even suspecting how close he was to the truth, Bolivar Trask claimed that Xavier was a mutant that needed to be detained in order to demonstrate the effectiveness of his mutant-hunting robots. However, as Trask was no expert in robotics, he had made a grave error. Designed to think for themselves and to adapt to any circumstances, the Sentinels found that to best way to protect humanity was to rule them.
Immediately, they disobeyed their creator and brought him back to their base. His presence being needed for the production of more Sentinels, the Master Mold threatened the anthropologist with the destruction of a nearby US city, 
should he not comply. Once the X-Men had located the Sentinel base in upstate New York, they tried to rescue Bolivar Trask, only for them to be captured alongside the robots' creator. During the Master Mold's interrogation of the Beast, Bolivar Trask learned of the X-Men's dream of peaceful coexistence and realized how wrong he had been about mutants. Shortly before the next wave of Sentinels would have been launched, Trask destroyed the Sentinels’ power source, which in turn destroyed the entire base and all Sentinels therein, even though he had to sacrifice his own life in order to do so. [X-Men (1st series) #14-16]