The evolution of Thai nicknames dates back to the Sukhothai era, when names were used to mark the order of children. Nicknames such as "Ai", "Yee", and "Sam" designated children as 'one', 'two', and 'three'. Later, in the Ayutthaya and Rattanakosin periods, children began to be named for physical attributes, such as "Daeng" ('red') or "Uan" ('fat') or for desirable items such as "Thong" ('gold'). Conversely, unflattering nicknames such as "Mah" ('dog'), "Moo" ('pig'), or "Gop" ('frog') were employed to keep malign spirits from coveting the child. King Mongkut (Rama IV) (1804–1868) stimulated interest in naming babies in accordance with astrological principles as outlined in the ancient scripture, "Namtaksapakorn".