I hope this is right, but when America was under Britain's rule, they blocked the trade, hoping to force the Americans to buy British products so the British could pay for the war. This just added to the fire. I think it also happened another time but I'm not sure. Hope this helps :)
Trade was a commonly used way to obtain items back in the day, people would give one item in exchange for another, allowing people to have access to items they didn't have before.
