Birds, as creatures believed to come and go between heaven and earth, were worshipped since
prehistoric times. Popular bird patterns used as decorative motifs evolved over time, from imaginary
birds like the phoenix and jujak (red phoenix) to cranes and magpies, each invested with different
symbolical meanings. The oldest roof tiles bearing engraved bird patterns date from the Warring
States Period of China. On the Korean peninsula, roof tiles with bird motifs first appeared with bird
motifs first appeared with popularity of Buddhist art during the United Silla Period ; especially
symmetrical motifs were popular.