But perhaps the most important of all Byzantine industries was the silk industry. Byzantine silks and heavy gold brocade were not only needed throughout the empire for church services and imperial functions. They, too, were widely shipped abroad. In the days of the old Roman Empire, all silk came from China, where Roman ambassadors had traveled 1,000 years before Marco Polo. The silk was carried by caravan across the desert to Samarkand, and then to the Persian border, where heavy duty had to be paid on it. Silk still came from China—and there was still a heavy duty on it—in the early days of the Byzantine Empire. But one day while Justinian sat on his throne two Christian monks appeared before him, one of them holding in his hand a hollow bamboo. He broke it open, and inside were silkworm cocoons. They had been smuggled all the way from distant Canton or Nanking. From then on, the Byzantines had a silk industry of their own. The silkworm was cultivated all over the empire, but especially in the Peloponnesus, the peninsula of southern Greece, which now became known as the Morea—the Latin word for mulberry leaf is _morus_—from the mulberry trees grown there for the silkworms to feed upon. Silk cloth was woven all over the empire, but principally in Greece and at Constantinople. As a matter of fact, some silk was even manufactured upon the very grounds of the imperial Sacred Palace. This was a special royal silk, and it was illegal to take any of it from the empire. Bishop Liutprand of Cremona—the same one who saw the emperor magically lifted up into the air at the Magnaura Palace—tried to smuggle some out of Constantinople, but he was caught. He tried to bluff his way through the customs by roaring, “Your emperor Nicephorus came to his throne by lying and crime! He told me I could buy all that I wanted to. Where is the imperial promise?” But although Liutprand was an ambassador from the German emperor, the Byzantines merely smiled at him. “You poverty-stricken Italians and Germans are not meant to appear in such gorgeous material. Only we Byzantines, who are unique in virtue, have a right to wear them.” They forced him to open his baggage and took five of the most splendid pieces. But they did pay him back the money he had spent. None of this Byzantine silk, and none of the other marvelous things they made either, would have added very much to Byzantine gold and glitter if the Byzantines had kept all for themselves. Little as the average Byzantine liked to risk his money in foreign adventures, it was foreign trade that brought most of their wealth.