Oh, I did read it. What part of this aren't you understanding?

"In the year 2246, the Followers of the Apocalypse sent a group of nine members to the Arizona wastelands to study the region’s tribal languages. The group included Follower Edward Sallow, who met with the New Canaanite missionary Joshua Graham, a specialist in tribal dialects. Not long into their travels, the group was captured by the Blackfoot tribe and held for ransom.

At the time, the tribe warred against seven other tribes, and suffered from a lack of skill in warfare. Against his companion’s wishes, Sallow aided the Blackfoots to save him and his companions from their captor’s enemies, giving them knowledge in gun maintenance, small unit tactics, explosive improvisation, and military strategy. The tribals admired Sallow so much that they made him their leader. With that, Sallow took the name Caesar, and began reorganizing the tribals he commanded into the Legion.

Caesar established warfare policies in the Legion based on the concepts of divide and conquer and total war. The Legion defeated the region’s seven tribes from weakest to strongest, and completely dominated each faction’s land and people. The people conquered in campaigns were conscripted, enslaved, or killed. Caesar saw the tribes “playing at war,” and tribals viewed his tactics as foreign, as their warfare consisted of skirmishes that never escalated into major conflicts.

With the combined leadership of Caesar and Graham, declared the "Malpais Legate," the Legion led campaigns against more tribes, forming a fanatically loyal army with their captives. Eighty-six tribes had been conquered by the year 2271, and the territory Caesar led formed the most powerful society east of the Colorado River. The Legion expanded west into the Mojave, and established Fortification Hill on the Colorado River in 2277. The advancing forces eventually made contact with the NCR near New Vegas, and began a campaign to take the region."