What were the traditional trade routes before the opening of new sea routes at the end of the 15th century?

Before the end of the 15th century, there were three main trade routes from the west to the east. One was the land route, the traditional "Silk Road", which landed in Constantinople, passed through Asia Minor, the Black Sea and the southern coast of the Caspian Sea to Central Asia, and then crossed

The Pamir Plateau to China. The other two are sea routes: one from Syria and the east coast of the Mediterranean, through the two river basins to the Persian Gulf, the other from Egypt through the Red Sea to the Persian Gulf, and then change ships to India and China. These trade routes

The road originally passed through merchants from Italy, Arabia, Byzantium and Persia and changed hands many times before goods could be transported to Western Europe.