Desecration of Ulgethon

The Desecration of Ulgethon was a year long violent conflict between the San'Shyuum Reformists and the Sangheili on the rocky world of Ulgethon. It marked the start of the War of Beginnings.

Background
In 938 BCE, the San'Shyuum Reformists discovered Ulgethon, a desolate planet that they believed to be entirely uninhabited. After making landfall with the Anodyne Spirit, a pioneer detachment was sent out to investigate a nearby repository of Forerunner relics. Arriving at the site, the San'Shyuum discovered the Sangheili—a sapient species they have never encountered previously—living among the Forerunner structures. While their initial meeting was amenable if tense, the Sangheili would soon discover the San'Shyuum's intentions with the holy relics. The Sangheili worshipped the Forerunners much like the San'Shyuum, but their stance on the manipulation of their gods' artifacts more closely resembled those of the San'Shyuum Stoics, considering it blasphemy to disturb them.

Conflict
When the San'Shyuum emissaries revealed their plan to excavate the Forerunner relics, Arbiter Vema 'Togad slaughtered and beheaded the delegation, sending their remains back to the Dreadnought atop a skiff. Horrified by the display of violence, the San'Shyuum immediately took the Dreadnought into the skies above Ulgethon, only to be intercepted by a fleet of Sangheili ships. The fleet engaged the keyship, but it proved to be effectively impervious to their weapons, resulting in the defeat of the Sangheili vessels. During their first battle on the ground, the Sangheili courageously faced off against the San'Shyuum's powerful Dreadnought from warrens and ridges across Ulgethon, using the most formidable weapons of war they could then fashion.

Ultimately, the San'Shyuum would use their Dreadnought to raze Ulgethon and eradicate its population. The conflict on the planet lasted an entire year and left the planet a charred husk filled with fallen warriors and shattered ships.

Aftermath
The Desecration of Ulgethon marked the beginning of a decades-long war between the two species, with the conflict spreading across many other Sangheili colonies and culminating in the Urs system.

List of appearances

 * Halo: Contact Harvest
 * Halo 2: Anniversary
 * Terminals
 * Halo Mythos: A Guide to the Story of Halo