Chang claimed to have been born in prehistoric times. Legends about him, however, seem to have accrued to a historical personality who lived in the 7th century and was summoned to the Imperial palace by two T'ang dynasty emperors. Chang, much preferring a secluded life to government appointments, refused to go. It is related, nonetheless, that on one occasion Chang visited the court of Emperor Hsüan Tsung (reigned 712–756) to perform feats of magic. In later times his picture adorned nuptial chambers, for he reputedly bestowed children on newly married couples.