When one walks into an Eastern Orthodox Church, one of the first things that one will notice is the images of Christ, the Virgin Mary Theotokos, and the saints depicted in icons and murals throughout the church. Icons depict the holy people of God who have gone before us and fought the good fight. They depict Christ and His disciples, and scenes from His life, miracles He performed, and parables that He told. Images of Christ and the saints date back to the beginning of Christianity. St. Luke the Evangelist is credited with painting the first icon of the Virgin Mary and Jesus in the first century. During the 8th and 9th centuries, the debate over the use of icons came to a climax with the iconoclastic periods where icons were destroyed and removed from churches. While the iconoclasts claimed that icons were a form of idolatry, the Orthodox Church argued that we don't venerate the icon itself, but rather we reverence the person depicted in the icon. St. John of Damascus argued that we can depict Jesus Christ in icons, because he was fully human and walked among His disciples. We can depict Him, because we saw Him. The 7th Ecumenical Council held in Nicaea in the year 787 confirmed the use of icons in the Church, and we celebrate this each year on the first Sunday of Great Lent (known as the Triumph of Orthodoxy) with the procession of icons.
Icons are also used in the home and other places outside of the church. Orthodox homes traditionally have a prayer corner, or home altar, which is decorated with icons of the family's patron saint(s) and other icons where the family says its prayers together.