Jointly Study War Machines
The war machines captured from the Machine Army have vexed your Mechanicals ever since they fell into your hands. While they are self-replicating and you still have access to them, and you know how to operate them and thus can still use them in war, you have made no progress on understanding their deeper workings. Sanctuary does not have technology nearly on this level, but they do have vehicles of their own and thus have a higher vantage point.
You pool your best minds in a joint research project, the engineers from Sanctuary teaching your Mechanicals how to build and repair their own vehicles. Their trucks, motorboats, and light planes are easy enough to grasp once you have schematics and can be taught the underlying theories, and your Mechanicals show rapid progress in designing their own versions; your military planners especially are interested in using the planes for military purposes. The motorboats in particular offer to rapidly change the volume and speed of trade on the river systems, and many merchants are clamoring to buy them, while others in the League are looking into integrating these machines into your supply lines, using them to replace your old inefficient overland systems of travel.
All of that aside, your joint research team throw themselves at the war machines. They discover that the machines are basically the same in fundamentals; they do not use any exotic methods of fuel or propulsion, and even their machine spirits are not too different from those either you or Sanctuary are familiar with. You are even able to understand the drones rather well.
The most complex part is the self-replicating nature of the machines. The support vehicles which allow the construction of new vehicle parts is fiendishly complex, and several have to be disassembled along with lesser war machines in various stages of aborted assembly, each of their parts individually analyzed. What you find only baffles your researchers further.
The support vehicles take in metal and other raw materials and, using a variety of different internal mechanisms, converts them into parts. They interact together in complex ways you only barely understand, although you are able to gain a few innovations from individual steps in the process which could be useful in more grounded industrial processes.
No, what your researchers struggle with is the lack of any control mechanisms whatsoever. It seems that what animates the support vehicles' construction and assembly system and guides it to build according to the established designs is the machine spirit itself. Sanctuary's researchers believe that, since these machines predate the Age of Unreason, there may have originally been a different system that oversaw the assembly process – perhaps the "computers" which only exist theoretically in Sanctuary's tech package. However, at some point, perhaps soon after they were uncovered by the Machine Armies, they developed animating spirits and the computational components withered away like vestigial organs.
Theories and speculations aside, you are able to successfully cultivate machine spirits to reproduce, and the first self-replicating technical rolls out of its shop in Sanctuary to great fanfare. The process is expanded to include boats, planes, and the other war machines you captured from the Machine Army. Moreover, now that you know how to induce magically-automated methods of assembly and construction, you could apply this to many other parts of your industrial base.
Speaker for Sanctuary
It is the first Sanctuary-wide election that the city has ever experienced, and it is, naturally, chaotic. It quickly becomes clear that the majority of potential candidates are members of the elite class of legal scholars, unsurprising since those are the most educated and respected individuals, although a few minor interest groups do run their own candidates. The primary candidates of course are those representing the pro-syncretism and pro-nativist factions, respectively.
The election takes the form of speeches, debates, and campaigning, all of it quite vigorous. The pro-syncretism candidate naturally argues for closer integration, cultural assimilation, and further political reforms to Sanctuary. The nativist candidate, surprisingly, offers a moderate view. Any hardline nativists of course would have refused to run, and the nativist candidate offers a vision of Sanctuary as an autonomous part of the League, free to practice its own culture without foreign influence.
A few clashes between supporters of one side or the other are reported, but the election itself goes smoothly. To your surprise, turnout is extremely high, perhaps due to the heated topics involved or simply the novelty of the situation. The pro-syncretism faction gains an even higher margin of victory than expected, perhaps due to the nativists' moderate candidate alienating more hardline members of his faction.
Still, as the first Speaker-for-Sanctuary arrives in Whiteclay to join the High Council, Sanctuary savors its first helping of democracy, and finds that it likes the taste.
Teach Spirit Veneration
The Sufi doctrine of Sanctuary may claim there to be only one God, but only a blind fool would deny the existence of other spiritual beings. Under their doctrine, spirits are intelligent, incorporeal beings who we are obligated to cultivate good relationships with, but they are not truly divine. The existence of beings like Lightning-Speaker or River-Woman is also accounted for. Certainly, they are powerful, owed a certain amount of respect, and perhaps one may request their assistance in certain tasks, but one wouldn't necessarily call that worship, would they?
In fact, some rather bold members wonder if the spirits themselves could not be converted, for which they claim there to be some precedent, but that is neither here nor there.
Still, while Sanctuary has cultivated good relationships with the nature spirits around them, using rituals they learned from their allies, and while they can fit those spirits into their doctrine, they remain unlearned in many of your ways. You set out to change that.
Their own customs regarding reincarnation mean that venerating the spirits of the dead isn't very applicable, but you can certainly teach them how to venerate the spirits of the trees and animals in more complex ways. There are few hunters or woodsmen among the urban-dwelling population of Sanctuary, but many of their allied tribes are eager to adopt your ways as, despite having converted to Sanctuary's faith, they still retain close ties to the land.
Following on that, you also begin to teach them about your major spirits. Lighting-Speaker, the patron and animating spirit of your electrical grid, is of course of primary importance as you and Sanctuary share that grid, and they dedicate their own electrical stations and transformers to Lightning-Speaker.
River-Woman also serves as a way to link your two societies together, as she governs the river that flows through the League and whose delta Sanctuary sits on. River-Woman's shrine in Sanctuary is an impressive structure, a monument of their architectural style. When they make an offering of goods, sinking a boat in the river delta, River-Woman herself makes an appearance as she does for you. She lays her blessing on the city, and your holy men believe that she has been greatly empowered now that her name is known along the entire course of the Long River.
Of course, Sanctuary does put their own spin on things. Their customs lead them reject designs such as idols or visual depictions of the spirits; instead, they favor swirling abstract patterns, or calligraphic murals which form the names of the spirits. Shrines to Lightning-Speaker feature wood panels with fractal burns created by running electrical currents through wooden boards. Meanwhile, shrines to River-Woman naturally feature abstract patterns meant to invoke flowing water. There are other notable additions – Sanctuary's mystics craft charms that invoke the spirits, or write poems about them in Arabic, or contemplate the mystical qualities of their written names.
Some of these aspects of veneration are even picked up by the rest of the League, as the interplay and exchange between your culture and Sanctuary's has strengthened your understanding of the world.