Silk is something found among the elites in the Heartland, in Lunar Tarsh, in Boldhome, and is quite common in Nochet, Rhigos, and Karse. Assuming the Lunar Empire has roughly the same level of elite access to silk as the later Roman Empire, it needs about 5 or 6 tons of silk per year. Going with the comparison, Kralorela exports about 10 tons a year or so through ships going to the Holy Country. Half of that stays in the Holy Country, the other half (5 tons) gets taken to Karse and loaded onto caravans going north. 1 ton or so gets taken en route by the Sartarite elites (mostly at Boldhome, but also at Wilmskirk and Jonstown) – that’s enough silk for 800 silk tunics or 1600 silk dresses. Ultimately around 4 tons of silk end up at Furthest.
Meanwhile, the Red Haired Caravan brings another 2 tons of silk or so in each year from the Kingdom of Ignorance. This comes from the roughly 6 tons a year Kralorela gives to Ignorance to keep them quiet.
In theory, you could put that all in one big silk caravan, but of course it isn’t. Each caravan might have one mule with silk – but that still is enough for about 60 silk tunics, which is going to be a good return! This is just a drop in the bucket of the somewhere in the vicinity of 900 tons of goods that gets sent each year up from the Holy Country to Furthest, which is carried by 2500 mules, probably a quarter of all the mules in Dragon Pass.
That’s about 35 standard 40 foot containers a year. Which isn’t all that much by modern standards, but is an awful lot in Glorantha.
One way of looking at it is that there about 2500 “mule loads” operating in Dragon Pass at any given time. Let’s say 5 are huge (1000), 10 are large (1000) and another 10 are medium (500). Small caravans are purely local and to be ignored. So the location of these 25 caravans are purely a matter of logistics. Since there are 56 days a week, there is going to be approximately 1 caravan arriving every other day.
So keep in mind that roughly every other day a caravan arrives in Jonstown or elsewhere along that main trade highway coming from the Holy Country. Presumably about the same volume is coming from the Lunar Empire as well. These caravans are the life blood of the Kingdom of Sartar, and so keep that in mind when you think about the economics of the kingdom.
There could be somewhere in the vicinity of 5500 to 6000 mules involved in the caravan trade through Dragon Pass (2500 carrying goods from the Holy Country, 2500 carrying goods from the Lunar Empire, 500 from Prax), which is probably more than half of all the mules in Dragon Pass.
This is part of that big explosion in trade following the Opening – which interestingly is about the time the Red Emperor takes a personal interest in Dragon Pass.
What are the Royal Roads is made of? The royal roads of Sartar are stone.