Cousins War
The Cousin War was an era of political upheaval and division in the Mutul spanning most of the 10th and 11th centuries. Traditionaly, the era start with the death of the last K'uhul Ajaw of the K'uy Dynasty, Nuhn Ujol K'inich II, and end with the coronation of K'ukumatz, first K'uhul Ajaw of the Nimabal K'iche Dynasty. The name is derived from a tradition saying that all of the first generation of pretenders were cousins of the late Nuhn Ujol K'inich II.
Many of the Mutals the pretenders formed had been de-facto independent long before 895, as the Chank'uy ability to control their territories crumbled after their disastrous wars with the Kayamuca Empire. there was near constant warfare between all the emerged Mutals, all claiming to be the sole legitimate inheritors of the Chank'uy.
The last of these regimes was the Western Mutal, conquered by the Nimabal K'iche Dynasty in 1093. It's only then that the K'iche were able to reclaim all of the former territories of the K'uy.
Background
The 8th century was a time of constant warfare and devastation for the Mutul with five conflicts against the Kayamuca Empire or its vassals. Almost all of the eastern regions of the Divine Kingdom were lost, as well as almost all of the eastern coast of the Xuman Peninsula. This left the K'uy Dynasty greatly diminished in prestige, wealth, and power. To ensure the security of the borders, they began to rely more and more on local generals, the Kaloomt'e, who were given the control of multiple market-cities in exchange for raising personal armies and defending the core regions of the Mutul against external threats. In an attempt to secure the loyalty of these "Imperators", the Divine Throne only granted the position to members of the House of K'uy, either minor lineages or cadet branches of the mainline. Similarily, the position of Kaloomt'e was not supposed to be transmissible from father to son, nor were they supposed to do more than perceive the tax revenues and organize the levies of "their" cities. But quickly, the Kaloomt'e acquired more and more powers due to the constant weakening of the Divine Throne.
The death of Nuhn Ujol K'inich II without an immediate heir nor a clearly defined successor accelerated the dissolution of the Divine Kingdom's institutions and brought the tensions between the cadet branches to new heights. Six pretenders rose up, all cousins of the late Divine Lord and five of which held positions as K'aloomt'e. Hun K'in K'uy, K'aloomt'e of the East, was the most prestigious of them but it's Sahal K'awiil, the only non-general among the potential candidates to the throne, who invited all the other pretenders to a "Convention" so they could negociate and elect a K'uhul Ajaw. Only five of the pretenders came to Uaxakatz'am to participate in the Convention. The sixth, Jasaw Chan Kan, K'aloomt'e of the West, declared the Convention a "mockery of the Law" and instead marched on Danguixh, occupying the ancient first capital of the K'uy and proclaiming himself K'uhul Ajaw there, convincing the prestigious clergy of the city to crown him.
The Convention was a failure and the pretenders couldn't find an agreement. Hun K'in K'uy returned to the eastern border, and he was imitated by the other Kaloomt'e soon after. Only Nuhn Kan Mah, the K'ol K'aloomt'e, did not return to his capital. instead, he joined a small mobile army he had gathered a few days on foot from Uaxakatz'am and then marched on the second capital of the K'uy. Sahal K'awiil managed to drive back his cousin's party, leading the levied citizenry of the capital despite his lack of military background. The K'ol K'aloomt'e then returned to his domain, his army plundering the lands on the way. Strengthened by this act, Sahal K'awiil convinced the Clergy of Uaxakatz'am to crown him K'uhul Ajaw. When news of it arrived to all the other pretenders, it sparkled protests and contestations, leading to all remaining four K'aloomt'e to proclaim themselves K'uhul Ajaw and reading their troops to defend their rights.
First Wars
War for Tzib’ajab and Muyalwitz
Between Jasaw Chan Kan, "Divine Lord of the West", and the rest of the Mutul were two provinces: Tzib'ajab and Muyalwitz. Neither of these provinces had been assigned to a K'aloomt'e and were thus "neutral" buffers between him and Sahal K'awiil who immediately moved troops to secure these regions. He successfully occupied Tzib'ajab, but the valley of Muyalwitz, too far away south and culturaly more amicable to the West than the East, recognized the K'uhul Ajaw of the West as the sole legitimate heir of the Mutul without a single battle.
In 897, Jasaw Chan Kan launched a massive offensive against the Tzib'ajab region, defeating his rival's armies and conquering the province in a single campaign season. But as he drew nearer to Uaxakatz'am, the resistance became more fierce and he was forced to stop a few dozen of kilometers away from the capital to strenghten back his army, secure his lines, and prepare a new campaign next season.
War for Uaxakatz'am
After his failed attempt to take Uaxakatz'am, Nuhn Kan Mah, the K'ol K'uhul Ajaw, decided against immediately launching the bulk of his troops against Sahal K'awiil as he was too concerned by his northern rival building up his own forces. Sensing the incoming conflict between Sahal K'awiil and the K'uhul Ajaw of the West, he waited and built up his own forces, only launching them in the direction of Uaxakatz'am in 898. Once again, his men plundered the lands on their way but on a much larger scale, until they finally the old capital and besieged it.
At the same time K'in Chan Chaak, K'uhul Ajaw of the North, led an army southward, following the eastern coast of the Xuman Peninsula until he finally reached Tzib'ajab in 898. Jasaw Chan Kan, K'uhul Ajaw of the West, worried by this unforseen intervention, abandoned his plan to attack Uaxakatz'am and moved his troops north to meet the Northerners army. He defeated them in battle, but was forced to wait another year before he could continue his onslaught eastward.
In a desesperate attempt to relieve the capital, a minor general loyal to Sahal K'awiil, B'alam Ek Witz gathered his own troops and launched an assault directly in the K'ol Mutal. At first unwilling the break the siege for such a minor action, the news of increased raids from K'in Chan Chaak to his north forced him to return to his Mutal to deal with both problems. Sahal K'awiil commited the mistake of following him, wishing to seize the occasion to destroy the K'ol army and secure his northern border. This weakened his western border, and Uaxakatz'am was seized by the Divine Lord of the West in 900.
War for Apikal
Sahal K'awiil met Nuhn Kan Mah in battle in 898 but was defeated. He was forced to rest in the Apikal Bassin to restore his strength, but the Divine Lord of the K'ol did not rest and fell on him in 899 in a bloody but undecisive battle. It's only the following year that Sahal K'awiil was defeated on both his eastern and western front, losing Uaxakatz'am and the Apikal Bassin.
Sahal was forced to flee south to the Mak'ab Plateau. There, he was able to repell the assaults of the K'ol and defeated a number of small western armies and parties in the Ch'ich Mountains. Jasaw Chan Kan and Nuhn Kan Mah facing each other in battle at Tupilchan also relieved Sahal K'awiil. Finaly, a new campaign from the Northern Mutal against its K'ol southern neighbor forced Nuhn Kan Mah to return back to his lands. The Westerner army led by Jasaw Chan Kan, tired by seven years of constant warfare, was further weakened when Sahal K'awiil's general, B'alam Ek Witz, was able in 903 to retake the city of Yaxalak at the feet of the Ch'ich Mountains and from there raid the westerners' supply lines, isolating them. Their K'uhul Ajaw tried to hold on to Uaxakatz'am, but was forced to abandon it in 907 and finally returned to Danguixh after a decade of warfare. By 911, Sahal K'awiil had also recovered the Apikal Bassin.
Eastern Expansion
Hun K'in K'uy, in his position of "Kaloomt'e of the East", was one of the most prestigious pretenders to the throne, having fought against the Kayamuca Empire and its allies many times, and had an important reserve of veterans in his cities and fortresses. For unknown motives, he remained passive for the first few years of the war, seemingly taking no action toward reclaiming the Mutul in its entirety.