The commemoration of St. Cosmas and St. Damian is one of the most ancient feasts of the Church, and these two martyrs have been honored in the East and West in many ways, including the building and dedication of churches in their honor in many places, including Rome and Constantinople. Along with St. Luke, they are the patron saints of doctors. Although we cannot be certain of the details of their lives, the information that has come down to us is of very early origin.
Saints Cosmas and Damian were venerated in the East as the "moneyless ones" because they practiced medicine at no charge. They were twin brothers, born in Cilicia (in what is now Turkey). They studied in Syria and became skilled physicians.
Since they were prominent Christians, they were among the first arrested when the great persecution under Diocletian began. Lysias, the governor of Cilicia, ordered their arrest, and they were beheaded in about the year 287. Their bodies, it was said, were carried to Syria and buried at the ancient Syrian city of Cyrrhus, which then became known as Hagioupolis – the City of the Holy Ones.
They were venerated very early and became patrons of medicine, known for their miracles of healing. The Emperor Justinian asked the heavenly aid of these saints, was cured by their intercession, leading the emperor to give special honor to the city of Cyrrhus where their relics were enshrined. Their basilica in Rome, decorated with beautiful mosaics, was dedicated in the year 530. They are named in the Roman Martyrology and in the Canon of the Mass, testifying to the antiquity of the celebration of their feast day.
Cosmas and Damian were not only ideal Christians by their practice of medicine as an act of Christian charity, but they also testify to God's blessing upon the science and art of healing, affirming the Christian understanding of the physical and spiritual unity of each person.
Almighty and Everlasting God, who didst enkindle the flame of thy love in the hearts of thy holy martyrs Saints Cosmas and Damian: Grant to us, thy humble servants, a like faith and power of love, that we who rejoice in their triumph may profit by their example; through Jesus Christ our Lord, who liveth and reigneth with thee and the Holy Ghost ever, one God, world without end. Amen.