Tin-glazed tiles produced since the 14th century in Spain. The word does not come from azul (blue in Spanish) but from the Arabic al-zulay (little polished stone). The term was first used to designate a composition of coloured tiles aimed at copying Roman North-African mosaics. It then became the common word for an entirely decorated tile of about 13 to 15 centimetres (5 to 6 inches). Panels of azulejos were first created in Seville around 1500 by an Italian painter, Francisco Niculoso. Niculoso was probably trained in a Della Robbia family workshop in Florence. The art of azulejos was developed and brought to its highest expression during the 17th and 18th century in Portugal.