Full Disclosure: Some days I'm lucky if I can correctly find my way out of my driveway [...before being ensnared by Free Republic, that is...]
Cheers!
The routes went through Bedouin territory, or Egypt at least, and every tribe had its own fee for safe transit, renegotiated every caravan. When the Romans held the routes, trade went to Rome, and India prospered. When Rome fell, so did India--collateral damage. Columbus sought to reestablish direct trade with India, which would restore both Europe (Spain, Italy) and India to a degree of wealth. America intervened, and somewhat later Jefferson tried continue Columbus' idea by establishing a route to China across the American West, which ran out of river, but by the time the railroads pushed across, New Orleans was the major port.