Time of Troubles

The Time of Troubles was a cataclysmic time period when the gods were forced to walk the earth in their mortal avatar forms. It was caused by Myrkul and Bane stole the Tablets of Fate from Lord Ao, and when no one would accept responsibility for the theft, Ao banished them to the Material Plane until the tablets were retrieved. Many deities, like Myrkul, were slain during the events, while others like Cyric rose to apotheosis as a result.

Further information

 * Time of Troubles at Forgotten Realms wiki
 * Time of Troubles at Wikipedia