Dear maester Steven, you’ve mentioned in the past that even though it is on the wrong side of the continent, Lannisport has become one of the largest cities in Westeros due its industrial activities. However, why do you think Oldtown was able to become even larger when the main exports of the Reach are only grain and wine?

According to the WOIAF, being the oldest seems to have been the key – it was an ancient trading post since before the Age of Heroes, so it’s on established routes, it’s got a baseline of carrying trade, etc.

In terms of exports, I wouldn’t knock wine or grain. Pre-Industrial Revolution, those are some of the major exports of a lot of countries because they’re always in demand and you can sell in bulk because everyone can usually afford to buy them.

Hence, wine and grain are growth markets – as economies prosper around the world, large numbers of people people will want more grain and more wine.

Spices, silks, gems, precious metals are really high value per weight, but the high price combined with a highly unequal distribution of wealth and income means that demand is coming from a limited number of sources. This means that more exotic goods are niche markets, and thus really exposed to swings in fashion and other fluctuations in demand. 

To give an example from the 16th and 17th centuries: yes, a lot of people got rich off of the spice trade. Used to be, a cargo of nutmeg or saffron was literally worth more than its weight in gold. But a lot of the longer-term innovations that would lead to the emergence of industrial capitalism came from more prosaic industries: the Dutch herring trade, for example led to new techniques in vertical integration of manufacturing and herring futures helped fuel the growth of the stock market in Amsterdam. The industrial revolution itself started in the production of cheap textiles, because there was a potential mass market for affordable clothing that there wouldn’t be for say, rubies and emeralds.