Majolica is an earthenware tradition built around an opaque, usually white, tin- or other-opacified glaze, painted with colored decoration on top of the unfired glaze before a single firing fuses both together.
Majolica's opaque white glaze base gives painted decoration a bright, even surface to sit on, in the same way a painter works on a prepared white ground rather than bare, absorbent clay. Colors are painted directly onto the dry, unfired glaze surface with metal-oxide pigments; because the glaze has not yet been fired, it is powdery and absorbent, which requires confident, largely uncorrectable brushwork, since a mistake cannot easily be wiped away and repainted the way it could on a wet or already-fired surface. A single firing then matures the glaze and fuses the painted decoration into it at the same time.
The name majolica comes from Majorca, the island understood to be a transit point for Hispano-Moresque tin-glazed ware reaching Italy from Islamic Spain, where tin-opacified glaze technology had itself arrived from the Islamic world's own innovations (see glaze's history). Italian production is generally dated from around 1350, with major centers including Faenza, Deruta, Urbino, Orvieto, Gubbio, Florence, and Savona producing sophisticated work for a luxury market by the late 15th century. The most celebrated Renaissance maiolica, known as istoriato ("painted with stories") ware, depicted historical and mythical scenes across a piece's whole surface rather than confining decoration to borders or repeating motifs. Closely related tin-glaze traditions spread across Europe under different regional names, most notably faience in France and Delftware in the Netherlands.
Because the decoration is painted onto an unfired, powdery glaze surface rather than a fired one, majolica painting is typically practiced with deliberate, confident strokes rather than layered corrections, and colors are chosen from pigments known to survive the glaze firing without burning out or bleeding into surrounding colors. Traditional Renaissance majolica painting worked from a deliberately restricted palette of five oxide-derived colors: cobalt blue, copper green, iron red, antimony yellow, and manganese purple, with blue and purple used mainly for outlining rather than filling large areas. The restriction was practical, not stylistic: these were the pigments known to hold their color and not bleed or burn out at the glaze's firing temperature, which is exactly the same constraint underlying the "colors chosen to survive the firing" point above.