Shinra

'''This is not FF7 canon. Well, some of it is. Most of it is not. This is mostly me trying to keep my notes straight. Spoilers abound.'''

FF7 and "Crisis Core" tell us that Shinra was a weapons manufacturer prior to the discovery of mako power in the early 1960s. We don't know who these weapons were being used on, though it is hinted in both "Crisis Core" and "Dirge of Cerberus" that there were conflicts prior to the famous Wutai War.

Mystery Wars aside, Shinra became a power company in the early 1960s, the first reactors going up in Midgar. Midgar was especially plentiful in mako, and was therefore ideal for the first mako power plants. At the time, the eight villages that later became Sectors were still standing, with Shinra setting up their corporate office in a central location among them. This was once a site sacred to Omega, though pretty much everyone has forgotten this.

Sacred Sites turned out to be Shinra's specialty. Most sites sacred to Summons also had high concentrations of mako and therefore eventually wound up with a reactor built on top of them. Even these, however, began to dry up, the land around them becoming barren. Rather than try to find a way to make mako reactors more efficient, or to come up with another energy source entirely, Shinra sought to locate a mako well that would never run dry. Having had good luck with the ancient gods so far, they decided to see if another myth was true: the fabled Promised Land. However, the Promised Land could only be found by those who could communicate directly with the Planet. Only the Cetra could do that, and they had been extinct for thousands of years.

Shinra caught a break when the fossilized remains of a Cetra monarch were unearthed in the ice: the Empress Jenova. The Jenova Project was launched shortly thereafter. The idea was to create a child bearing Jenova's DNA, and then to follow that child to the Promised Land. It didn't go quite according to plan. Other projects were launched attempting to accomplish the same thing: Project Gillian, Project Sephiroth, and a number of unnamed attempts bred in Deepground. Although several above-average children were born, none of them have so far proven to be able to communicate with the Planet.

Rather than scrap the projects, Shinra chose to tweak them slightly, training the children bearing Jenova's DNA to be the ultimate super-soldiers. It was discovered not long after that Jenova's cells would have a similar effect on adult males (females less so). The SOLDIER program was born.