This term is used to refer to the times before the Revolution. It is a time without recorded history, as the Apt understand now. Beetles, Ants and Flies were mere slaves, cowed by the powerful sorceries of their masters that they couldn't even comprehend.
The Lowlands were ruled by the Moth-kinden, with the assitance of the Mantis-kinden. This relationship is summed up in the commonly used phrase Masters of the Grey, Servants of the Green. The Moths were opposed beyond the borders of the Lowlands by the other powerful Inapt kinden: Mosquito, Slug, Centipede and Assassin Bug. All of these are now thought to be mythical. Spiders and Dragonflies also rose to prominence during this time, but were less aggressive.