Shadows of Absalom
The Eight Ages of Golarion
Age of Creation: Golarion comes into being. Aboleths are believed to be the first intelligent life on the planet, with other races coming about as a result of the Gods. Also: The big evil deity of Rovagug is locked away in the center of the planet by the Gods. The major players in this are Saranae (The Goddess who actually beat up Rovagug and threw him in there), and Asmodeus (who provided the locks and chains that keep him in there.)
Age of Serpents: The Serpent Folk, sometimes called the Yuan Ti, rule the world.
Age of Legend: The empire of Azlant came into being, as did the empire of Thassilon, ruled by the evil Runelords. That all went to hell when the Aboleths use their magic to cause the Earthfall.
The Age of Darkness: A meteorite called the Starstone falls to Golarion, destroying Azlant and basically wrecking everyone. The Elves retreat to the First World till things blow over, and the Dwarves (still underground at this point) start climbing up towards the surface, which will take them a few centuries to actually get here.
Age of Anguish: Humanity starts rebuilding after the Earthfall; Gnomes come to Golarion from the First World.
Age of Destiny: Ancient Osirion is established as one of the great empires of the inner sea. The Kelesh empire settles Qadira. A lot of other nations are found during this period including Taldor, Geb, and Nex.
Age of Enthronement: Aroden raises the Starstone and founds Absalom. Aroden becomes a god. Three other people take the Star Test in this period, in this order: Norgorber (The assassin) Cayden Caliean (The drunk sellsword) and Iomedae (A Knight of Aroden who led crusades against Tar Baphon). Cheliax is founded during this period. And the Elves finally come back when a demon named Treerazer moves into their homeland and starts destroying it. Also, Tar Baphon, now a lich known as the Whispering Tyrant, is finally put in his place and imprisoned in his lair in Ustalav. The era ends with everyone preparing for Aroden's big return where he plans to take humanity to the next level.
Age of Lost Omens: Aroden dies. And everything officially goes off the rails. The Worldwound opens back up after Aroden sealed it a while back, Cheliax spends a few decades in civil war till they get taken over by Devil worshipers, and as a result many of their former subordinate nations break free and go independent, most prominent of them being the Andoran, which goes democratic. Since Aroden's death, no major prophecy has come true, a condition for which historians have named the current era.