The Choral City was the capital city of the planet Isstvan III.[1a]
History
Before the coming of the Imperium, the city was known by the human inhabitants of Isstvan III as Khry Vanak - it was renamed "Choral City" (a Gothic translation of its original name) after the planet was brought into compliance in the Great Crusade.[1a]
Older than the Imperium by millennia, Choral City was a magnificent architectural wonder dedicated to the their Gods, the chief deity being Father Isstvan. At its centre was the Precenter Palace, a dizzying structure of marble blades and arches that made exquisite use of light, glittering in the sun like a marble orchid. Outside of the Choral City's perfect architecture were its multi-layered residential district sprawl of glass and steel, with intermixed countless bridges, walkways, and boulevards lined with lush trees and greenery. The eastern side of the city marked its industrial district where skeletons of steel structures rose high and belched smoke, butting up against the mountains to the east.[2a]
The Sirenhold (Siren-hold) is arguably the most awe-inspiring portions of the city, if not it is undoubtedly the most prominent culturally. Marked by its monolithic walls surrounding its tomb-spires, the monolithic sculptures depicting the mythological past of the Issvanians: Father Isstvan singing the world into being, subsequent wonders of life He created, and darker legends of the Lost Children. Those who forsook their father were banished to the wastelands of the Isstvan system's fifth planet Isstvan V where they became treacherous and brooding mutants. Legends of War, treachery, revelation and death are displayed all around the wars, and thus the lives of the inhabitants of Choral City below are suffused with their divine purpose. The gods of Isstvan III were said to sleep beneath the Sirenhold.[2a]
The ceremonial guardians of this the Precenter Palace wore ornate gleaming armour of a shining metal which their halberd blades were also made of. Their face plates bore the masked visage of a face wrought in stained glass, the mouth represented with dark leading and filled with gem-like triangular teeth.[2b]
Rebellion
When the newly-appointed Imperial Commander of the Isstvan System, Vardus Praal, rebelled against the Imperium, he rallied the locals and their religious order of Warsingers to his side to overthrow Imperial rule. Claiming that the Lost Children would return for war and the prophecies of myth were coming true, he had the populace prepare for the inevitable Imperial retribution accordingly.[2a]
Mortarion's Expeditionary Fleet would receive an Imperial distress signal from Isstvan III by chance. Having been received at least 2 years after being sent, the message warned that Praal and the Warsingers had overthrown the Imperial government. The last Imperial survivor being the message's sender, an individual from Corvus Corax's 27th Expeditionary Fleet following the Compliance of Isstvan III.[2c]
The Emperor of Mankind ordered Warmaster Horus to crush the rebellion with extreme prejudice. The battle that resulted was a major turning point in the history of the galaxy, as it saw the open declaration of Horus's own rebellion against the Imperium.[1b]