Siduri War
The Siduri War (also known as the First Great War, or the Great Siduri War) was a continent spanning war that lasted from 4 April 1934 to 11 February 1938. Nearly 60 million military personnel were mobilized for the conflict, and over 25 million people were killed. It was the largest and deadliest conflict in Siduri history and had profound impact on the political and social history of the involved states.
After centuries of dominance by various imperial powers, the countries of Siduri began coalescing into distinct nation-states of their own accord. The largest exception was the Cacertian Empire, which had unified in 1871. Heavily industrialized with a large economy and military, the Cacertian Empire proceeded to establish itself as the premier superpower, conquering and annexing Lirinya and Knichus in the 1880s before forming a political union with Shirvaniya. The Empire's efforts to control the Sundering Sea led to conflict with the young Republic of Syara in the Divide War, which ended in a surprising Syaran victory in 1918. Syara's subsequent rise as a major power, fueled by a growing industrial base, economy, and population, was matched by increasingly nationalist endeavors by the Republic, which came to a head with the election of President Sasko Anastasov in 1924. Anastasov sought to unify Siduri into a pan-continental alliance to oppose the Cacertian Empire, resulting in the creation of the Inner Sphere power bloc in 1929, although only the Shirvani Dominion joined.
Tensions between Cacerta and the Inner Sphere only exasperated already poor relations with the Inner Sphere and Ruvelka, which Syara saw as a Cacertian ally and puppet due to Cacertian support for the Imperial Separatists during the Ruvelkan Civil War. This culminated in the Invasion of Ruvelka on 4 April 1934 by Syara, which is typically used to mark the beginning of the war. The Shirvani Dominion invaded Ruvelka a month later, and the Principality rapidly collapsed but never officially surrendered. The invasion, intended to demonstrate the capability of the Inner Sphere and intimidate the other Siduri powers into supporting the IS instead resulted in widespread condemnation. In July 1934 the Cacertian Empire, Quenmin, Tennai, Mansuriyyah, and Ruvelka's government-in-exile formed the Common Axis to oppose further Inner Sphere aggression. In response, the Inner Sphere invaded Quenmin, Tennai, and Mansuriyyah in October 1934.
Most of the fighting took place along these fronts, the largest and bloodiest of which was the Quenminese Front. Extensive mountain warfare took place on the Tennaiite Front, and a war of maneuver and far-reaching operations broke out across the Mansuri Front in the Western Theater. Instead of the rapid victory the Inner Sphere had hoped for, the war developed into a war of attrition, marked by large scale offensives and heavy loss of life in both sides. Unable to secure a victory on land, the Inner Sphere attempted to gain naval supremacy but were defeated at the Battle of the Sabri Sea. By 1936 the Common Axis armies and their increasingly sophisitcated armored operations began pushing the Inner Sphere back, despite occasional IS victories. In early 1937 the Inner Sphere was expelled from Quenmin during Operation Kunai Grass, and shortly afterwards was forced to withdraw from Tennai entirely. In the spring of 1937 the Common Axis launched an invasion of Shirvani Dominion itself, which led to the collapse of Ceymur Agilli's Presidency. The Dominion subsequently switched sides and Syaran forces were expelled from the country, who retreated into occupied Ruvelka. In September 1937 the Common Axis commenced the Liberation of Ruvelka, and by January 1938 Cacertian and Quenminese forces had forced the Syarans back to the Kurilla Mountains, while Mansuri forces broke through Syaran defenses along the Matra Mountains. Amid uprisings by the Ruvelkan populace and the collapse of the Armed Forces of the Syaran Republic, Anastasov committed suicide and Syara sued for peace on 16 January.
The Treaty of Debrecen, signed on 10 February 1938, officially ended the war. The Inner Sphere was dissolved, and Syara and Shirvaniya were required to pay war reparations that totaled the equivalent of $550 billion. The treaty restored pre-war borders between Ruvelka and Syara, which angered many Ruvelkans due to Syaran control of Zemplen. Quenmin annexed Kansdoen shortly after the war, and Shirvaniya was also forced to cede territory to Mansuriyyah. Defeat in the war and economic hardship brought upon by the cost of the conflict tanked the Syaran economy, and the country entered into what became known as the Broken Years. The Republic never fully recovered from its defeat, and was dissolved at the end of the Syaran Civil War. Despite its victory, the cost of the war led to the steady dissolution of the Cacertian Empire, which gradually granted independence to its various colonies and client states.