The Divergence and Post-Divergence

Divergence
Hoping to seal away the Betrayer Gods for good, the Prime Deities retreated from the Material Plane. Behind themselves and their defeated brethren, they erected a barrier known as the Divine Gate, which would prevent any god from physically crossing over into mortal realms.

The departure of the gods from Exandria, and the diminishment of their influence, was an event that has since come to be known as "The Divergence."

Post-Divergence
“Much time has passed since, and the world has been reborn once again. The gods still exhibit their influence and guidance from beyond the Divine Gate, bestowing their knowledge and power to their most devout worshipers, but the path of mortals is now their own to make.” – The Myth of Exandria

The events of Critical Role take place during the fourth age of Exandria. This timespan encompasses all of modern history since the Divergence. Monks of the Cobalt Reserve and other historians label and number the years in the Calendar of Tal'Dorei as "PD", or "Post-Divergence". For example, at the start of the new campaign, the year is 835 PD.

Influence of the Gods
Though unable to physically cross over into Exandria, both the Prime Deities and the Betrayer Gods still grant boons from afar to their mortal followers. Vasselheim remains as the bastion city of the Prime Deities, where divine magic is common but arcane magic tightly regulated for its role in unleashing the Calamity.

Vestiges of the Divergence
Powerful relics from the war against the Betrayer Gods remain scattered throughout the planes of existence. Eight of these relics have been gathered together by a group of heroes known as Vox Machina, though more remain lost.