Glazed ceramics are used in architecture since at least the 6th century BC, as the magnificent Ishtar Gate, partially reconstructed in the Berlin Pergamon Museum, testifies.
Glazed tiles decorated with intricate geometric patterns and Arabic writing were for centuries, and still are, in widespread use in the Islamic countries and for westerners remain one of the most recognizable and constant marks of the beauty of mosques. From their origin in the Middle East and flourishing in the Islamic world, glazed tiles spread to Spain and Portugal, to Italy, the Low Countries and most of Europe.
Modern majolica was perfected in Italy during the 15th century and saw an early architectural integration in the works of Luca Della Robbia. A representative work is the vault of the Capilla del Cardinal del Portugallo in the church of San Miniato al Monte (Florence) where the tondi protrude from a covering of patterned glazed tiles, curiously of the same pattern as later used in façade glazed tiles manufactured in Lisbon in the 19th century.
Tondi by the Della Robbia and other artists were also used to decorate façades, as testify the cases of the Spedale degli Innocenti in Florence, the magnificent early 16th century portal to the church of the Convento Santa Paula in Seville and the façade of the Madre de Deus monastery in Lisbon (today the National Azulejo Museum of Portugal) where Della Robbia tondi were set on to the façade around 1515.
Glazed ceramic tiles are used as decorative panels or as finishes of whole walls and façades in several countries, such as Portugal, where they started being produced during the Renaissance and developed as a preferred means of finishing architectural surfaces, becoming ubiquitous in palaces, churches, gardens and bourgeois houses.

Under the influence of Chinese porcelain and Dutch productions in the famous Delft Blue, cobalt blue painting over a white tin glaze eventually became prevalent and inextricably associated with the baroque architecture of both Portugal and Brazil.During the 19th century azulejos found a new utility in Portugal, lining the façades of urban multi-storey buildings, not only for decoration, but mostly for utilitarian purposes, a unique development again shared only with Brasil. A number of other glazed decorative pieces, including statuary, was also routinely integrated in buildings of the Romantic era.
Glazed architectural ceramics represent outstanding pieces of technological and decorative achievement while Portuguese azulejos integrated in architecture are one of the most original contributions of the country to the common cultural heritage of Mankind, justifying a series of international conferences on the theme of integrated glaze ceramics that Laboratório Nacional de Engenharia Civil (LNEC) started in 2009 and now pursues in cooperation with Museu Nacional do Azulejo (the Portuguese National Azulejo Museum - MNAz).