Altars in Christian churches that are under the same ecclesiastical canons as the high altar, but considered subordinate to the high altar. Side altars are typically placed at the head of a side aisle, along the sides of the aisle, or in a bay or chapel; they are often decorated with an altarpiece, wall paintings, windows, or other art referring to the titular saint to whom the altar is dedicated. Rules may state the allowable size, number of steps, or absence of a tabernacle for a side altar. Side altars were ranked in importance; the side altar on the Gospel side of the high altar had the highest status, and the counterpart on the Epistle side had the second highest rank. Side altars appeared in church architecture by the 6th century; they became prime places for members of the congregation to display their wealth and importance through patronage.
