Altarpiece unclear. 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. Retable-type altarpieces are often made up of two or more separate panels created using a technique known as panel painting. The panels can also display reliefs or sculpture in the round, either polychrome or un-painted. It is then called a diptych, triptych or polyptych for
Perugia Altarpiece panels portray scenes of the "Life of St. Nicholas" <br> Perugia Altarpiece The Perugia Altarpiece (Italian: "Pala di Perugia") is a painting by the Italian early Renaissance painter Fra Angelico, housed in the Galleria Nazionale dell'Umbria of Perugia, Italy. The painting was executed for the St. Nicholas Chapel in the Basilica of San Domenico, Perugia. In the early 19th century, it was split and partially dispersed, and some of the predella panels were acquired by the Pinacoteca Vaticana. In Perugia were executed copies of these panels, enclosed into a neo-Gothic frame. The polyptych also included some small depictions of saints,