Trade routes will form along the easiest, cheapest path between two trade hubs (villages, cities etc). Generally this is the shortest route, along rivers and along the coast/ across the sea. Traders will avoid dangerous routes which are home to bandits, outlaws, dangerous animals and anything that would threaten their cargo, unless they can hire the muscle to protect themselves.
Writing Trade Routes
This is a method of writing down trade routes which I came up with.
Each trade route will have a name (if only for your benefit) and a year it was established and perhaps a year it was no longer in use. Using the above example, there are three nodes (trade hubs) on this route, Rivermeet, Messa and Longubassa.
In brackets indicate the country this node belongs to. Then list goods traded on this route (makes it easier to understand when you look back at it later.)
Then write the flow. Goods in the brackets between these nodes indicates the goods traveling between the two nodes. + Indicates a flow from left to right, – indicates from right to left. A good in italics indicates that this node produces the good. Rivermeet (Grain+) Messa would mean Rivermeet produces grain and exports it to Messa.
As the route changes over time, either add, in brackets the year that good began being traded, or add to a timeline like the example below.
Goods: Grain, Fish, Lumber, Game Meat, Cattle Meat, Naval Supplies
Flow: Rivermeet (Grain+, Fish-, Lumber-, Game Meat-, Cattle Meat+) Messa (Grain+,Fish-, Cattle Meat+, Naval Supplies-) Longubassa,
On my map, I have indicated trade routes using a yellow dotted line like you can see above. See how some of the settlements act as major trade hubs where several routes intersect. These will be prosperous cities.
Cities on Trade Routes
Settlements on trade routes will prosper and grow. Those that produce or consume goods will grow as a direct result of the trade, but other industries such as inns and entertainment will grow as services and goods are provided to those visiting the settlement.
Villages that lie on a trade route, but don’t trade much may grow as well as traders stopping for the night and restocking their food and water would bring wealth to the village.
Villages near where trade routes intersect will prosper also and may turn into a central trade hub in its own rights over time.
Using Trade and Resources to Drive Your World
In addition to growing cities, wars might also be caused. A nation that does not have access to an iron source might invade to secure such a supply. An inland country might invade a coastal one to acquire access to fish stocks. Countries might fight over control of certain trade routes, as they did the Silk Road in real life. Prosperous villages, towns and cities, will become targets for raiders, bandits and outlaws and who knows, the noise of the city might attract some nasty critters.
Taking the time to add resources and develop trade routes can really breath life into your world and give it new and interesting directions that you hadn’t even thought of. Someone on the Worldbuilding Subreddit (the community this blog is born from) once said (and I wish I knew who),
“The mark of good worldbuilding is when the world starts to build itself.” ~Unknown Redditor