We’ve all got access to the Lunar Way now and to the Glorantha Sourcebook, so we have access to the history of the Lunar Empire. But how did the Lunar Way grow to where it has over 1.5 million dedicated initiates?
The Lunar Way started out small – initially just the Red Goddess, her immediate followers and companions. Many quickly flocked to her banner in the war against the Carmanian Empire, but there was not really a cult at all until after the First Battle of Chaos in 1232. Over the next two decades, the Red Goddess was able to teach some of her followers her insights and magical secrets – I expect Illumination and special Lunar Magic came first (along with Chaos Gift and a few other such spells), and only later regular Rune cults.
In the First Wane, there were many who received the Lunar Way directly from the Red Goddess or at least from her first generation of followers. Later the cults were led mainly by people with no first-hand experience of the Red Goddess. However, the Red Emperor remained a conduit between the Red Goddess and the people. He remained an undying witness to his Mother’s deeds and teachings.
The Seven Mothers appealed to many in the Lunar Heartlands who worshiped the Solar gods. The Solar deities submitted to the Red Goddess after Castle Blue, and the Seven Mothers cult grew steadily in the Lunar Heartlands during the early Wanes. However, I suspect it was still largely a cult of a select elite, with Seven Mothers missionaries working among the friendly Lunar Heartlands population to teach the Lunar Way. The Lunar Empire was governed by a condominium of Yelmite/Lunar nobles.
In the Fifth Wane, the Lunar religion changed, as did the Lunar Empire. Thousands of Pelorian peasants and soldiers joined the Seven Mothers and Hon-eel cults, and were settled throughout the Lunar Heartlands and in colonies in the Provinces. By the Sixth Wane, the Lunar religion was fully integrated into the local pantheons of the Heartlands and Saird, with Lunar cults becoming a plurality in most satrapies. However, the Red Emperor was no longer an ageless witness – instead he was a “constantly reincarnating demigod” who would die and then be replaced by a new mask.
In the Orlanthi lands to the west and south of the Lunar Heartlands, acceptance of the Lunar Way was slow if at all. Colonies of settlers from the Heartlands were bright crimson islands in a sea of Orlanthi barbarism. Successes in Tarsh, Vanch, and Holay need to be seen against a backdrop of failures in Aggar, Imther, Grazelands, Sartar, and Prax.
Now I think at the end of the day, the difference between the missionaries’ success in the Heartlands versus the Hills comes down to having better mythic resonance in the Heartlands. The Solar deities acknowledged the Red Goddess and her right to exist. Orlanth and his brothers never did. And whereas Illuminated Chaos is tolerated in Solar Peloria, it is anathema amongst the Orlanthi and Praxians.
Note that the Sable Riders worshiped a celestial entity that was revealed to have a Lunar connection, they pretty much follow the pattern set for the other Solars.
Sylila is less out of the ordinary that you’ seem than you’d think. The area around Jillaro (which became Hwarin Dalthippa’s base of operations) had been ruled by Dara Happans (as part of Henjarl) for the century before the birth of the Red Goddess and had rulers with strong celestial ties in the late Second Age. Hwarin Dalthippa’s success was more as a conquerer than as a missionary. That being said, all those references to the Lunar religion being fully integrated into the local pantheons in Saird and the successes in Holay – well that refers to this.