For a long time, indeed right up to the end of the fifteenth century, scarcely anything but Moorish geometric patterns seem to have been used. Then with the renaissance their place was taken by other patterns of infinite variety; some have octagons with classic mouldings represented in colour, surrounding radiating green and blue leaves;[25] some more strictly classical are not unlike Italian patterns; some again are more naturalistic, while in others the pattern, though not of the old geometric form, is still Moorish in design.

Together with the older tiles of Moorish pattern plain tiles were often made in which each separate tile, usually square, but at times rhomboidal or oblong, was of one colour, and such tiles were often used from quite early times down at least to the end of the seventeenth century.

More restricted in use were the beautiful embossed tiles found in the palace at Cintra, in which each has on it a raised green vine-leaf and tendril, or more rarely a dark bunch of grapes.

Towards the middle of the sixteenth century the Moorish technique of tilemaking, with its patterns marked off by raised edges, began to go out of fashion, and instead the patterns were outlined in dark blue and painted on to flat tiles. About the same time large pictures painted on tiles came into use, at first, as in the work of Francisco de Mattos, with scenes more or less in their natural colours, and later in the second half of the seventeenth century, and in the beginning of the eighteenth in blue on a white ground.

Towards the end of the eighteenth century blue seems to have usurped the place of all other colours, and from that time, especially in or near Oporto, tiles were used to mask all the exterior rubble walls of houses and churches, even spires or bulbous domes being sometimes so covered.

Now in Oporto nearly all the houses are so covered, usually with blue-and-white tiles, though on the more modern they may be embossed and pale green or yellow, sometimes even brown. But all the tiles from the beginning of the nineteenth century to the present day are marked by the poverty of the colour and of the pattern, and still more by the hard shiny glaze, which may be technically more perfect, but is infinitely inferior in beauty to the duller and softer glaze of the previous centuries.

When square tiles were used they were throughout singularly uniform in size, being a little below or a little above five inches square. The ground is always white with a slightly blueish tinge. In the earlier tiles of Arab pattern the colours are blue, green, and brown; very rarely, and that in some of the oldest tiles, the pattern may be in black; yellow is scarcely ever seen. In those of Moorish technique but Western pattern, the most usual colours are blue, green, yellow and, more rarely, brown.

Later still in the flat tiles scarcely anything but blue and yellow are used, though the blue and the yellow may be of two shades, light and dark, golden and orange. Brown and green have almost disappeared, and, as was said above, so did yellow at last, leaving nothing but blue and white.

Although there are few buildings which do not possess some tiles, the oldest, those of Moorish design, are rare, and, the best collection is to be found in the old palace at Cintra, of which the greater part was built by Dom João i. towards the end of the fourteenth and the beginning of the fifteenth century.

Formerly all the piers of the old cathedral of Coimbra were covered with such tiles, but they have lately been swept away, and only those left which line the aisle walls.