There are many legends in China about the discovery of silk and the silk moth.
One is about the Empress Lei Zu, wife of the Yellow Emperor. She was drinking tea under a tree when a cocoon fell into her cup. When she picked it out of the tea she found the end of a strand and unraveled it and wrapped the silk thread around her finger. When the silk ran out, she saw a small caterpillar. In an instant, she realized that this caterpillar was the source of the silk.
The Chinese guarded the art of silk manufacturing for 3000 years, successfully keeping it a state secret. It was prohibited and punishable by death to take the cocoons and eggs out of the country.
So, for many centuries, silk fabrics could only be found in China.