Merrouroboros

Merrouroboros was a super-continent in existence on the planet Abeir-Toril during the Days of Thunder and before the First Sundering of Abeir from Toril. Merrouroboros was bordered on the west by the Silver Sea and on the south by the Great Blue.
After the creation of the planet Abeir-Toril, that world had a great Ice Age, which ended in approximately −35,000 DR. At this time, the continent of Faerûn did not yet exist; instead, Faerûn was joined with Kara-Tur, Maztica, and Zakhara as part of Merrouroboros.
The saurian sarrukh were the first to establish an empire on Merrouroboros, ruling over most of the land that would later be Faerûn. They were followed by the fey, who established the realm of Faerie around −34,000 DR. Third came the amphibious batrachi empires, coming to prominence some 500 years later and peaking around −31,500 DR. Lastly, the avian aearee empires emerged.
Merrouroboros ceased to exist around −17,600 DR in the great cataclysm known as the First Sundering, which caused the super-continent to break apart into Faerûn, Maztica, and Katashaka, and the appearance of Evermeet.

Maps

• 

  Days of Thunder

  A map of ancient Abeir-Toril 37,000 years ago

Type

Continent

Location under

Toril