Sts. Cosmas and Damian were twins born in Arabia in the third century. Their parents were Christian, and the twins became doctors, known for their skills and the fact that they offered their services for free.
Many of their patients converted due to their charity and Christian witness. But because they were so well-known, the brothers were two of the first targets when the Diocletian persecutions began at the end of the third century.
In 287, Cosmas and Damian were captured and told to deny their faith in Jesus. They refused, and were put through a series of tortures, including crucifixion. Miraculously, they remained unharmed. When their torturers became tired of trying to get them to deny Christ, they simply beheaded them.
The Church includes Sts. Cosmas and Damian in the Litany of the Saints and the Canon of the Mass.