became freer and painters exploited the possibility of laying paint on in broad, visible and varied brushstrokes. Oil paintings initially became a popular method for producing altarpieces and soon replaced tempera for this purpose. The ease with which large paintings could be created meant that not only did very large altar paintings proliferate, taking the place of polyptychs made of small panels, but because they were of relatively light weight, such pictures could be used on ceilings, by setting them into wooden frames and without the trouble of the artist having to work laboriously on a scaffold. Famous Venetian painters, Titian, Tintoretto and Veronese produced many such pictures. Peter Paul Rubens painted a Passion of Christ in a number of large canvases. Wood Because the nature of wood lends itself to easy working it has been a favoured material for decorative fittings within churches. It can be carved, veneered and inlaid with other materials. It can be lacquered, painted or gilt. It can be used for artefacts and free-standing sculptures. It is relatively robust unless finely carved, but must be protected from mould and insects. In the Byzantine period ivory rather than wood was the preferred material for carving into small religious objects, caskets, panels and furniture, the throne of Maximianus of Ravenna, with carved reliefs of Biblical stories and saints, being the finest example. The oldest large wooden sculpture to have survived in Europe is the painted and gilt oak Crucifix of Archbishop Gero (969-971), in Cologne Cathedral. Subsequent to this time, there are an increasing number of surviving large Crucifixes and free-standing statues, large and small, often of the Virgin and Child. Much of the wooden furniture in churches is richly decorated with carved figures, as are structural parts such as roof bosses and beams. Carved and decorated wooden screens and reredos remain from the 13th century onwards. In Germany, in particular, the skill of making carved altarpieces reached a high level in the Late Gothic/Early Renaissance. In Belgium wood carving reached a height in the Baroque period, when the great pulpits were carved. Metal Christian metalwork can take a vast number of forms, from a tiny Crucifix to a large statue or elaborate tomb or screen. The metals used can range from the finest gold leaf or silver filigree to cast bronze and wrought iron. Metal was commonly used for Communion vessels, for candelabra and all types