The term 'maiolica' is believed to have its roots in the medieval word for 'Majorca', which was on the route for ships bringing Hispano-Moresque wares from Spain to Italy. The term originally referred to both Italian and Spanish-made wares with a lustre finish but later came to be associated exclusively with tin-glazed pieces with brilliant colours, although analysis of Italian maiolica pottery from the Middle Ages suggests that the chemical composition of the glaze often varied. Technological developments during the fourteenth century meant that the colour palette expanded from more traditional manganese purple and copper green to include cobalt bluem antimony yellow and iron-oxide orange. Maiolica developed in various locations in Italy, with notable early centres of production including Romagna, Faenza, Bologna, Orvieto and Deruta. Later, during the sixteenth century, centres were established at Castel Durante, Urbino, Gubbio and Pesaro, with the development of istoriato, in which realistic biblical, historical and mythological scenes directly linked to Italian Renaissance painting were painted with great accuracy and skill, representing a golden age of maiolica. Some of the principal centres of maiolica production, such as Deruta and Montelupo, still operate to this day.