The picture at the left shows a schematic model of an iconostasis wall. The idea of the Iconostasis originated in the Byzantine era. At first, an iconostasis was just a small wall (threshold, fence), a symbolic marker of the division between the Sanctuary and the Nave, that is, between the heaven and the earth (the Divine and the human). This little wall was not meant to prevent the faithful who came to worship in the Church from seeing the Sanctuary. The Byzantines never envisioned the separation of the sanctuary from the nave by such a "material" veil. They used a low marble or wooden fence to display the icons of those saints who were celebrated on a particular day to all believers. Since the placement and removal of the icons from the top of this low wall turned into an everyday chore, the icons were permanently installed on the wall. With time, the iconostasis wall consisting of several tiers (rows) of icons was developed. Around the fifteenth century, Russian iconostases reached as many as five or six rows of icons. The first, original row, called The Sovereign Row (Mestnyi Chin), had to include the icon of Christ, placed to the right of the door (red rectangle). Sometimes, instead of Christ, that icon showed the saint or the Biblical event to which the church was dedicated. Another required representation in the Sovereign Row was an icon of the Virgin, placed to the left of the door (pink rectangle). The second row was usually either the Festival (Liturgical Feasts) Row (Prazdnichnyi Chin), presenting events related to the life of Christ and the Virgin, or the Deesis (Deisusnyi Chin), often the largest and most important row. The icons in the Deesis row had to include at least three icons: Enthroned Christ in the middle, flanked on his left (on the right from the viewer's point of view) by John the Baptist, and on his right (on the left from the viewer's point of view) by the Virgin. If there was space to include more icons in the row, they were arranged in a particular order: Archangel Michael next to the Virgin and Archangel Gabriel next to John the Baptist, Peter next to Archangel Michael, and Paul next to Gabriel. In very large iconostases the most celebrated Fathers of the Church as well as most venerated saints could be placed in alternating order on each side. The last two rows, the Prophets' Row (Prorocheskii Chin) and the Patriarchs' Row (Praotecheskii Chin) were also interchangeable. The access to the Sanctuary was gained through the Holy (Beautiful, Royal) Door (Tsarskie Vrata), decorated with the images of the four Evangelists or the Church Fathers. The rounded top of the door was often a favorite place to depict The Annunciation, while the space above the door could be occupied by a representation of The Last Supper. [S.C. and A.B.]