Spoiler
Jeff Richard sur the Middle Sea Empire of the Second Age:
A few notes on the Middle Sea Empire of the Second Age. It was largely a naval power (with its main land power being Seshnela), and it could throw massive resources at problems. Teams of sorcerers enslaving elementals and other spirits to *force* things their way, rather than working in accordance with the gods (like using sails instead of elementals to power your ships). They were humanistic rather than monotheistic - the world exists to be understood and exploited by humankind. The gods were studied, even used - but they were tools to power, rather than ends in and of themselves. Think of them as scientists in the science fiction novels of the 1960s and early 70s.
Unlike the Rokari or New Hrestoli, the Jrusteli were perfectly willing to support and participate in cults and learn their mysteries. Issaries and Lhankor Mhy were both spread throughout the world by the Middle Sea Empire, and probably Chalana Arroy as well. Aurelion was used to tame Caladraland, and Wachaza was the backbone of their naval power. The Grain Goddesses were used for better harvests, without the political dangers of Ernalda (and her husbands that were allies of the EWF).
Did I mention that iin the height of the Second Age, the Jrusteli had something like Melnibonean battle barges? Sorcerers enslaved water elementals to move them, and the barges were loaded up with Wachaza worshiping cultists. These ships required huge resources but would have been absolutely terrifying. Catapults and ballista on the ships, these things would be totally impractical without the magical resources of the Middle Sea Empire. But with their sorcerers and Wachasta cultists, they were mobile floating temples of Death and War.
The thing about the God Learners is they tended to do things with pure magical brute force. They didn't develop more sophisticated craft techniques, better agricultural practices, smarter tactics and combined arms - because they didn't need to. Need a navy? Let's build huge armoured barges and have water elementals move it around. Need better barley harvest? Let's move the Grain Goddess from another region and put her here. Need to deal with many different cultures? Let's put Issaries here and have his markets be neutral grounds. In short, they thought like power-gaming RPG players.
Don't think about the God Learners as being "wrong" - they clearly understood how the magical rules of Glorantha worked well enough to exploit them in extravagant ways. But like a gamemaster dealing with players who abuse rules loopholes one too many times, the cosmos struck back with a Rules Fix.
The God Learners were shocked and surprised when their expansion into southern Genertela was halted and even reversed by armies of dragonewts, dark trolls, and elves, led by Lightbringers riding atop wyrms and dragons. Fire-breathing dragons burned battle barges, and waves of dragonewts who fought without any care for their lives terrified the well-armed soldiers who fought for the Emperor. Even worse were the troll ambushes at night.
That's an important trick to understanding the success of the EWF. By speaking with dragons, they gained the service of the dragonewts, wyrms, dream dragons, and countless other draconic entities. And that magic did not fit well within the paradigm of the God Learners monomyth. The techniques that allowed the Jrusteli to conquer Slontos, Kralorela, Fonrit, and more, grounded to a halt in Dragon Pass.
All this and much much more will be in the Cults Book.