War of Many Banners

The War of Many Banners was a multi-faction conflict that took place across Sangheili space roughly between 995 BCE and 960 BCE. Primarily fought between the Crimson League, Thar'shi Sphere, and Nirphal Resurgence; several other far smaller factions also participated in the war. The intensity and scale of the fighting ebbed and flowed over its duration.

This was the final large scale civil conflict prior to the War of Beginnings and the creation of the Covenant.

Initial fighting at Suban
Fighting between the Crimson League and Thar'shi Sphere broke around Suban proper. This fighting was initially limited to the moon itself, as neither side wanted to escalate the conflict into their other holdings or their heartlands on Sanghelios. This lasted for several years and was mostly fought by local forces. Escalation aversion eventually melted away as the local forces depleted, requiring the introduction of colonial forces into the battles.

The Nirphal Resurgence
In the midst of the fighting, a number of colonies and vassals from both factions attempted to secede from both in a loose coalition known as the Nirphal Resurgence. This included a few states on Sanghelios proper, colonies in the Joori portion of the Urs system, as well as interstellar colonies.

By the 980s BCE, the Nirphal Resurgence confronted the Crimson League in a number of places in the Urs system.