By the time of the Almohade invasion or very shortly after--that is, towards the twelfth century,--the Spanish Moors had grown acquainted with glazed earthenware. Indeed, the Almohades are believed by some authorities to have actually introduced it. Gestoso, on the contrary, suggests that Spain may have transmitted it to Africa. However this may be, the Almohades used it largely in the decoration of their homes and public buildings in Andalusia; first as _aliceres_ or bands composed of smallish pieces running round a room, and subsequently in the more effective and more useful form of _azulejos_ proper. The Spanish Moors employed the word _almofassass_ to designate both _aliceres_ and _azulejos_. Nevertheless, the two were not identical, although Riaño takes them to be so. He says: "The earliest tiles or _azulejos_ made in Spain are composed of small pieces let into the wall, forming geometrical patterns." These, in fact, were _aliceres_. It is not so easy to define an _azulejo_. We read in Aben-Said, quoted by Al-Makkari: "There is another kind of work employed for paving houses. It is called _azzulechí_ and resembles _mofassass_. It has wonderful colouring, and replaces the coloured marble used by the people of the East to decorate their chambers." This definition is not completely clear. Those of the Christian-Spanish writers are not more satisfactory. Covarrubias calls these objects "small bricks, square and of other shapes, used for lining chambers in the mansions of the wealthy, or in garden paths." Nebrija calls them _tessela pavimenticia_, adding that they bear the name of _azulejos_ because the earliest ones were of a blue colour--a statement which Dozy supports by instancing the Persian-Arabic _zaward_ or "blue stone." Gestoso resolves the question sufficiently for our purpose by showing that the term _azulejo_ is usually applied to square tiles of a largish size, the length of whose sides varies between eleven centimetres and eighteen centimetres, _aliceres_ being properly the smaller strips or pieces (technically known as _cintas_ or _verduguillos_) used in a bordering or frieze. Other decorative pieces of small dimensions, invented in the fifteenth century, were called _olambres_ or _olambrillas_, and served to lend variety to the red or yellow brickwork of a pavement or a floor.