The term on its own usually refers to miniature paintings up to a few inches across. Miniature portraits were developed from illuminated manuscript work and were popular from the 16thC onwards. They are usually in watercolour or gouache; early examples are on vellum and from the 18thC on ivory. Oil miniatures are rare, generally dating from the 16t …... Found on http://www.encyclo.co.uk/visitor-contributions.php