The Seven Machabees, brothers, and other Jews, suffered martyrdom for their faith in the second century before Christ, under the tyrant Antiochus Epiphanes, the impious King of Syria. They are the only martyrs who suffered before Christ that are honored with a feast of universal observance. Their relics were placed in the church of St. Peter’s Chains beneath the new altar on August 1st.
(Source: The New Roman Missal, Rev. F. X. Lasance)
The chains with which St. Peter the Apostles was fettered from time to time have always been the object of veneration among the faithful. They are preserved in a basilica in Rome, which is called St. Peter ad Vincula (in chains). The anniversary of the dedication of this church falls on August 1st. The chains of the Apostle Paul are preserved in the Basilica of St. Paul. The reverence shown to the chains of the two apostles must have been very widely spread in olden times from the moment when Justinian 1 asked the Pope for “a portion of the chains of the holy apostles, if it were possible” and St. Gregory the Great relates that in his day the faithful were eagerly desirous of the favor of possessing at least a small quantity of the filing’s of St. Paul’s chains. The chains of St. Peter are in two portions, one having eleven links, shaped so as to hold the hands, and the other twenty-three links, at the end of which are two half circles to hold the neck. Only four links are preserved of the chains which bound St. Paul.