The First Era - The Age Of Beasts
The First Era is characterized by nomadic tribes of all races scattered throughout the world.
It began when the world was created and ended when the first nations of elves and dwarves appeared.
The Second Era - The Age Of Dragons
The Second Era is characterized by the supremacy of elves and dwarves. The elves built a surface empire of magic; the dwarves built an underground empire of machines. These empires stretched throughout the world.
The Second Era ended when conflict between elves and dwarves destroyed both empires.
The Third Era - The Age of Anarchy
The Third Era is characterized by the supremacy of goblinoids, who built on the ruins of the elven and dwarven empires.
The Third Era ended when humans, strengthened by holy power, began building settlements capable of holding back the goblinoid armies.
The Fourth Era - The Age of Spirits
The Fourth Era is characterized by scattered nations of each race, none particularly stronger than any other, engaged in holy wars with each other. Although men were the first to use the power of the gods the other races quickly learned to access their own deities.
This is the current era.