Quick catch-up of history and geography
The oldest traces of the silk road date back to twenty centuries BC. It started from China and ended in Antioch, a now Turkish city, on the border with Syria. It is on this road (which started from the province of Shaanxi and passed through Xinjiang then between Samarkand and Kabul to finally cross Persia) that Marco Polo distinguished himself.
The incense route, also old, linked the ports of the West coast of India to those of the Arabian Peninsula, which the goods, once unloaded, crossed on camels.
From ancient times, the spice route followed roughly the same route and Egypt was the main player. From the 9th century, this spice trade passed into the hands of the Venetians and the Arabs. Then, this half-maritime, half-terrestrial route is in competition with the maritime route linking Europe to India via the Cape of Good Hope, opened by Vasco da Gama in 1498.