Cassander's Rebellion

Cassander's Rebellion
Part of the Ulmian Rebellions
A 2884 painting of the Siege of Sillas (738-740)
Date 738–740 Location Southern Sillas Result Decisive Sillenic victory: All-out defeat of rebel forces Loyalist forces suffer heavy losses Extensive depopulation of Southern Sillas Annihilation of Oriental Ulmian community outside of North Olmac and Metropolitan Sillas Persecution of Ulmians (incl. Ulmian Anystesseans) and Paleoanystesseans begins Split of Oriental Ulm from Orthodox Ulm Establishment of Anystesseanism Territorial changes Status quo ante bellum
Belligerents
Sillenic Empire	Orthodox Ulmians under Patra of Vandenapolis, Cassander Kasumartza's Clique
Commanders and leaders
Mikaela Romana Anystesses Andreas Kebekense Agustina Romana	Kasumartza Sarda † Cassander
Units involved
Sillenic Army • Legions I–X • Peasant militias	Kasumartza's army • Allied militias Cassander's guard • Azourian mercenaries
Strength
100,000 soldiers 200,000 peasant militias	80,000 rebels 10,000 Cassander's guard force 25,000 Azourian mercenaries
Casualties and losses
Total: 1,000,000 killed, 86 fortified towns and 1,700 villages razed

Cassander's Rebellion (Classical Sillenic: Depellion Ni-Kassandre, Old Olmac: Lepelíon Ni-Kassantel) was a civil war fought between the Orthodox Ulmians of Sillas, led by Kasumartza and Cassander, the latter of whom is the leader of the Orthodox Ulmian Church in Sillas; and the legitimate government of Sillas, led by Empress Mikaela. Fought between 738 and 740, the conflict is the first of the three major rebellions involving Ulmians, and is thus sometimes known as the First Ulmian Rebellion.

Ulm first arrived in Sillas in 480, with the arrival of Apostle Cassander and 800 of his followers. They founded Vandenapolis (now Iesikapolis) and married into the Sillenic population while maintaining their religion. By the seventh century, the Ulmian community in Sillas developed beliefs that would later characterise Oriental Ulm, such as the practice of full body immersion, emphasis on good works and ascetism, lack of an episcopal structure, and its own interpretation of Ulmian religious laws. In 640, Empress Vandena converted to Ulm and formally established the Ulmian Church of Sillas, which was in communion with the Orthodox Ulmian Church in Azoz. By 700, about 30% of Sillenes professed Ulm, which was well-represented in every region of Sillas. Only about one out of five Ulmians in Sillas actually practiced "orthodox" Ulm, with the remainder practicing a wide variety of beliefs characterized as Oriental Ulm (or Sillenized Ulm). With Sillas' ulmicization coinciding with the height of the Occidentalizing Period, many scholar-nobles and upper class Sillenes were attracted to Ulm and Western culture. Under Vandena's daughter, Vandenina, Ulm was briefly established as Sillas' sole official religion. Vandenina unsuccessfully tried to impose Ulm onto her other subjects, which led to her being widely unpopular across all religious groups. She also rescinded the policy of tolerating heterodoxy and initiated the persecution of Oriental Ulmians, which she and the Orthodox Church viewed as heretical. Following her death in 738, reactionary elements within the Imperial Council rescinded Ulm's status as the state religion. The withdrawal of state patronage provoked Cassander into calling for rebellion.

The Storming of Vandenapolis signified the start of the insurrection, with Cassander declaring the establishment of the Heavenly Kingdom of the North, an oppositional state under the nominal jurisdiction of the Orthodox Ulmian Church. Exploiting the succession crisis arising from Vandenina's death, Cassander and his co-belligerent Kazumartza, who previously led the oppositional faction of the Imperial Council, rapidly gained control of Southern Sillas and slaughtered thousands of Oriental Ulmians and pagans alike, as well as forcibly converting thousands more into Orthodox Ulm. The goal of the insurrection was many-fold; they sought the conversion of the Sillenic people into Orthodox Ulm, and the transformation of Sillas' culture and government. The borders between the two parties eventually stabilized, and the conflict eventually devolved into total war, though neither side made significant advances into each other. The Imperial Council elected Mikaela, a general, into the throne, though she would fail to subdue the rebellion by herself. In the spring of 740, Anystesses, aged just 18, visited the Imperial Court. Anystesses claimed to the Anointed One (iu-Susi in Sillenic, or in her native Olmec, yō-Tzixi) of Ulmian Eschatology, and requested 100,000 to defeat Cassander. Initially ridiculed, she was allowed joint-control (with Andreas the Apostle) over a legion of 10,000 after accepting a challenge in which she would be granted her request in-exchange for shooting an arrow at an apple mid-air from 400 yards. While Mikaela was hesitant to allow a young, illiterate Ulmian girl to be given command of any troops, Anystesses would lift the Siege of Sillas in just seven days, and subdue the rebellion by June 21 of that year. Kasumarza and other native collabortors were condemned to slavery, while Cassander was deported back to Azoz. While personally grateful for her service, Mikaela would submit to clerical pressure and reluctantly give Anystesses to Ulmian authorities, who would torture her for 40 days before burning her at the stake under the charge of crossdressing, lesbianism, and heresy. According to Anystessean tradition, Anystesses was resurrected in December 25, gave the Final Sermon and Grand Commision to the Apostles, and ascended to Heaven, an event that was reportedly witnesses by many around Vandenapolis at the time.

While only lasting two years, Cassander's Rebellion resulted in the extensive depopulation of Northern Olmac and parts of the Central Basin, with a total of a million deaths representing a fourth of the population before the insurrection. Some areas did not recover in population until the Imperial Era. The Oriental Ulmian community in particular was devastated to an extent it is sometimes described by scholars as a genocide; however, Oriental Ulm continued to remain strong in its "heartland" of Northern Olmac (centered around Vandenapolis), as well as Sillas City itself. Despite being instigated by Orthodox Ulmians only, the extensive damage caused by the rebellion permanently harmed the perception of Ulm; the proportion of Ulmians fell from a peak of 30% to 18% immediately following the war's end, and eventually stabilized at 10% due to a combination of mass apostasy (both voluntary and involuntary) and localized pogroms. It also caused political thought to become more isolationist, cautious, and conservative. The decline of Ulm and the subsequesent push to "renativize" Sillenic culture led to profound cultural changes, including: the eventual disestablishment of the Orthodox Ulmian Church in Sillas (with the Holy Patra of Vandenapolis being expelled in 74X), the consolidation of the Sillenic Solar Cult, a revival in Sillenic philosophy and folk religions, the further development of Oriental Ulm, and the growth of the Paleoanystessean Church.