This is done by arrangement with individual companies or by legislation. These flags were made of silk. Knights in the Middle Ages carried pointed flags called pennons . A knight's promotion to a higher rank was symbolized by having the end of pennon cut off. The resulting square flag was called the banner , and the knight become a knight-banneret .
National flags are among the most recent kinds of flags.
They first came into use during the 1700's in Europe and North America. Until then, most flags stood for the personal authority of rulers. Flags at sea. Before the days of radio, a complicated system of flag design and display grew up around the need for communication at sea. Flag codes enabled the sending of messages between ships or from ship to shore.