Answer:
- Trade through the Silk Road with China became more difficult at the end of the fourteenth century, when the first Ming emperors erected fortresses and placed garrisons of troops in the west with the intention of containing possible threats of invasion. Meanwhile, the secrets of silk production were already known even in Europe, and in the early fifteenth century, Lyon was producing most of the silk that was consumed in Europe.
- Maritime trade through the so-called Species Route developed considerably. Maritime transport offered more efficient and safer commercial options than caravan attempts to cross the increasingly dangerous Taklamakan basin.
As the Chinese and other nations were increasingly engaged in naval commerce, the economies of various cities and oases along the Silk Road, in Central Asia and northwestern modern China, which depended heavily on international trade suffered enormously. Except for the largest cities with the largest water supplies, the communities gradually abandoned themselves, until they were swallowed by sand. In this way, the millenary Silk Road came to an end under the policy of isolation of the Ming dynasty, in the mid-fifteenth century.