"A portrait miniature is a miniature portrait painting, usually executed in gouache, water colour, or enamel. Portrait miniatures developed out of the techniques of the miniatures in illuminated manuscripts, and were popular among 16th-century elites, mainly in England and France, and spread across the rest of Europe from the middle of the 18th-century, remaining highly popular until the development of daguerreo types and photography in the mid-19th century. They were especially valuable in introducing people to each other over distances; a nobleman proposing the marriage of his daughter might send a courier with her portrait to visit potential suitors. Soldiers and sailors might carry miniatures of their loved ones while traveling, or a wife might keep one of her husband while he was away. The first miniaturists used water colour to paint on stretched vellum. During the second half of the 17th century, vitreous enamel painted on copper became increasingly popular, especially in France. In the 18th century, miniatures were painted with water colour on ivory, which had now become relatively cheap. As small in size as 40 mm × 30 mm, portrait miniatures were often used as personal w:Mementosmementos or as jewellery or snuff box covers."