of existence ruled all of Bas-Lag for a period of 500 years. The Ghosthead, as these entities were known, originated on another world in a different plane of existence somewhere on the eastern rim of the universe. Seeking a milder place to live than their homeworld, which was torn between a vicious cycle of days and nights that created oceans of molten iron and froze the very atmosphere, the Ghosthead built a "metal fish" and used it to find Bas-Lag. Their arrival created The Scar, a massive physical and dimensional rift on Bas-Lag's surface from which different existential possibilities leak. The Ghosthead harnessed the energy from The Scar with a process called "possibility mining", and used their power to gain control over all of Bas-Lag, manipulating possibilities to their advantage. The Ghosthead Empire was ultimately destroyed by a rebellion called the Contumancy, followed by a period known as the Sloughing-Off. The Empire's history survives long after its fall in documents such as the Imperial Canon, and in lost technologies and structures, like Possible Swords and Possible Towers, still scattered in hidden places across Bas-Lag. Malarial Queendom The Malarial Queendom was a short-lived empire built by the anophelii, with territory in Rohagi, Shoteka, and the Shards. Some two thousand years before The Scar, the Queendom collapsed and the anophelii were nearly eradicated. The remaining anophelii were driven to a small island south of Gnurr Kett, where they are kept in isolation as captive scholars for the Gnurr Kett nobility. First Umbric Age The time period in which the Bas-Lag novels are set, the First Umbric Age, is the period of infighting and feuding that occurred between the various states on Rohagi after the Ghosthead Empire departed. The calendar used by New Crobuzon (at least) marks its years from the start of the First Umbric Age. Full Years The Full Years were New Crobuzon's golden age, when the city had achieved its greatest advances in science, technology, and thaumaturgy. Decline set in during the late 15th century, however, and some of this knowledge was lost. Desperate to prove that the golden age was not at an end, New Crobuzon constructed a massive ship, the largest in the world at that time, intended to be the pinnacle of New Crobuzon industry. The Grand Easterly was a boondoggle, however, suffering from several design flaws. It was briefly converted into an ineffectual warship during the