Occasionally, the demarcation between what constitutes the altarpiece and what constitutes other forms of decoration can be unclear.[1] Altarpieces can still broadly be divided into two types, the reredos, which signifies a large and often complex wooden or stone altarpiece, and the retable, an altarpiece with panels either painted or with reliefs. Retables are placed directly on the altar or on a surface behind it; a reredos typically rises from the floor.[2]