The Fifth Era of Erlemine is relatively new, being only in its thirty-fourth year. Each era is defined by some major event, the first being the longest. The First Era is also called the Time of the Elder Beings.
The Second was defined by the freedom of the mortal races won during the Dawn War, when the Elder Immortals left Erlemine.
The Fourth Era was defined by a reigning peace after the Great War. It became known as the Time of Waiting as Erlemine waited for some great defining event. When that event came, it became the start of the Fifth Era, official cementing the Fourth Era as the Time of Waiting. That event was the discovery of Pocor on the edge of the Uncharted Lands.
Many historians are tentatively calling the Fifth Era the Time of Exploration and Expansion, though that is rather optimistic, as the Fifth Era is still in its infancy, and tension hangs over the world as the fate of Pocor is debated by the nations of the east and west.