Today the Eastern Church commemorates the chains which held the Apostle Peter when he was imprisoned in Jerusalem by King Herod Agrippa and which were broken by an Angel to facilitate his escape. An account of this happening is related by St. Luke in Acts 12:1-19. The chains were kept by the Church in Jerusalem where they were venerated by visiting pilgrims. In the fifth century, St. Juvenal, the Patriarch of Jerusalem, presented them to Eudocia, wife of Emperor Theodosius the Younger, who took them to Constantinople.
Eudocia later sent a portion of the chains to Rome with her daughter Licinia Eudoxia, the wife of Valentinian III. Licinia Eudoxia built the church of S. Petrus ad Vincula on the Esquiline Hill to house the relic. Already in Rome were the chains with which Peter was bound when he was imprisoned by Nero. These latter chains were placed together with the chains from Jerusalem. The Western Church venerates these combined miracle working chains on August 1st.
The chains kept in Constantinople were presumably lost during the fall of that city in 1453, although I believe that portions of these chains had previously been distributed to Mount Athos and others had perhaps found their way to Russia.
I mention this feast primary to reference today's days reading from the Greek Synaxarion and it's words about the veneration of relics in general.
Herod Agrippa, the grandson of Herod the Great and king of the Jews, grew wroth against the Church of Christ, and slew James, the brother of John the Evangelist. Seeing that this pleased the people, he took Peter also into custody and locked him up in prison, intending to keep him there until after the feast of the Passover, so that he could win the favour of the people by presenting him to them as a victim. But the Apostle was saved when he was miraculously set free by an Angel (Acts 12:1-19). The chains wherewith the Apostle was bound received from his most sacred body the grace of sanctification and healing, which is bestowed upon the faithful who draw nigh with faith.
That such sacred treasures work wonders and many healings is witnessed by the divine Scripture, where it speaks concerning Paul, saying that the Christians in Ephesus had such reverence for him, that his handkerchiefs and aprons, taken up with much reverence, healed the sick of their maladies: "So that from his body were brought unto the sick handkerchiefs or aprons, and the diseases departed from them, and the evil spirits went out of them" (Acts 19:12). But not only the Apostles' clothing (which certainly touched the bodies of the sick), but even their shadow alone performed healings. On beholding this, people put their sick on stretchers and beds and brought them out into the streets that, when Peter passed by, his shadow "might overshadow some of them"(Acts 5:15). From this the Orthodox Catholic Church has learned to show reverence and piety not only to the relics of their bodies, but also in the clothing of God's Saints.
Pictured above is my own reliquary. From top and then left to right; S Patrick, Bishop; S Sebastian, Martyr; S Bonitatis, Martyr; S Germain de Granfeld, Martyr *; Ss Sebastian & Catherine, Virgin Martyr; at the bottom are physical remembrances of a personal friend.
* S. Randoald, the companion of S. Germain is pictured next to S. Sebastian on the icon which is my profile picture.