The Golden Age
The Golden Age was a period of peace during which the Firstborn expanded their knowledge and presence, codified their religious beliefs, and built up their cultures. Because of the relatively small number of Firstborn conflicts were few and the Peace of Isolation reigned for many years. As the time since the Immortals had walked among them faded into the past the Firstborn began to form churches, formal and informal, to pass along their religious beliefs. Their cultures became more complex as the imminent return of A-dui came into doubt.
The Secondborn appeared in the latter half of the Golden Age. Most of the eight Secondborn races came into close proximity of one of the Firstborn and gradually adopted the cultural traits of this Firstborn race. However they remained uniquely different in many ways and often created their own communities. The Secondborn, while shorter-lived, had children more quickly and had larger families, thus their populations grew more quickly.
The expansion of Secondborn communities and the competition between them for the best resources eventually led to the Border Wars. These wars were small, often skirmishes, and usually involved just the groups in the local area. However the growing enmity between races led to greater battles which ended the Golden Age.