In response to the question whether RQ has too strong social commitment for its characters (I think it doesn't, BTW), I started researching the origin of guilds and similar fraternities.
These things crop up when cooperation of folk not related through family ties is required to ensure a benefit for all participants. This is the same prerequisite that led to the formation of cities, but cities are not a prerequisite for formation of guild-like structures, only a breeding ground because they tend to bring together people from different family backgrounds. This lack of family ties is the main difference to clans. The concentration on the here and now and usually a lack of organized priesthood and shrines is the main difference to a cult.
Guilds are fine existing in an environment controlled by other authorities, as long as they get their say in what they regard as internal matters. These internal matters usually imply privileges that force non-guild members to seek certain services exclusively from guild members.
Infrastructure often is managed by guild-like associations – whether irrigation or coastal protection, road maintenance or maintenance of fortifications. Often controlled and created by authorities, but not necessarily so – coastal protection at the continental North Sea shores worked as communal effort without any higher authority when the coastal communities still were farmer republics, and continued to work in that fashion under feudal and absolutist rule.
The term guild in its role as an association of business folk appears to be of German origin.
A precursor to the guilds were the collegia (https://en.wikipedia.org/wiki/Collegium_%28ancient_Rome%29) of the Romans. When new cities were founded in the Germanies, guilds crop up in the early middle ages or the late dark age. German Wikipedia offers the origin of the term guild as old Norse "gildi", meaning companionship, association or carousal.
"Guild" is one of the few cases where German has a lot more terms than English - the German "Gilde" is restricted to merchants, mutual insurance associations, and defence associations ("Schützengilde").
In German, associations of crafters have different names like "Zunft" (from "ziemen", to befit) or "Innung" (Einung, roughly: union, and yes, with a strong element of trade union responsibilities in addition to creating an exclusive, inaccessible market with all its obvious benefits for the practitioners).
Some guilds had their founding hero/saint, like the knudsgilde - a merchant guild that took the sainted father of King Waldemar of Denmark (who got murdered in peace negotiations which could have resulted in him becoming King of Denmark, and who had worked towards protection of merchants crossing the cimbric peninsula at Schleswig as duke of that region). Wikipedia articles available in German, French, Danish and Swedish.
So: guilds are mostly an urban phenomenon, as only cities can support more than one specialist crafter in a place. However, once in place, the rural specalists would join the urban associations for their specialist knowledge (in Glorantha: crafts, sorcery and lore).
When Sartar founded his cities, he introduced the crafters and merchant associations to Dragon Pass. This is a parallel to the Greek and Phoenicians foundig their colonies around the mediterraneans, or the wave of cities founded in the Baltic region which led to the Hanseatic League.
Sartar modeled his cities on the cities in his native Heortland, which have a history reaching back to the late Dawn Age (or further, as in the case of Old Karse), and are an imitation of the cities of Esrolia (which reach back into the Golden Age) and/or God Forgot (which bring the Golden Age Malkioni tradition of city building into the region).
Now, people might say that cities have nothing to do with the heroes of the Ilias. However, that is not quite the case - most of the heroes before Troy were kings of their home cities, or champions for them. Being kings usually means having some deity few generations past in the male lineage.
We don't find any mention of crafters' or merchant guilds in the Ilias, though.
Few artisans are mentioned in Greek mythology. There is Daedalos, and there's Hephaistos the god of smiths, and the carpenter/shipwright of the Argo. Odysseus' horse has no named builder.
Crafter heroes are rare in the myths I am most familiar with. Daedalos, Wayland, Ilmarinen, soon followed by historical masters remembered for their works (Archimedes, the Alexandrine artificers). Crafting deities other than domestic crafts are quite rare, too – the Tuatha de Danann field an unusually high number. The Norse gods rely on outsiders – giants, svartalfar, dwarfs. And when they get the goods, they aren't ready to pay the price.
There is hardly any pantheon without a smith figure, though (https://en.wikipedia.org/wiki/Category:Smithing_gods). The Norse Wayland appears to be a rather weak and later addition, though.
Such heroes or deities had no need for guilds, of course. But e.g. the helpers of Hephaistos would form a fraternity.
Greek mythology does provide something like guilds, like the Idaean Dactyls https://en.wikipedia.org/wiki/Dactyl_%28mythology%29#Idaean_Dactyls or nations of metallurgists like the Telchines https://en.wikipedia.org/wiki/Telchines, both listed as precursor cultures included in the Hellenes.
From the bureaucratic records for the tomb builders at Gizeh we know that the ancient Egyptians had specialized crafters in the bronze age. Corraling the elite of these into a secluded city probably started something like an association, too. While these folk toiled away at Gizeh, other monuments were built by the kings and the temples, and there seems to have been an exchange of patterns and styles between the tomb builders and those crafters working elsewhere in Egypt.
RQ2 mentions the name "guilder" for the standard silver coin for "the city of Corflu, run by various guilds." This must have been written before Biturian's visit...
