Cosmas and Damian were third century Arabian-born twin brothers who embraced Christianity and practised medicine and surgery without a fee. This led them to be known as the holy unmercenaries, the Anargyroi. They cured blindness, fever, paralysis and reportedly expelled a breast serpent.

Saladino d'Ascoli, a 15th century Italian physician, claims that the medieval electuary, known as opopira, a complex compound medicine used to treat diverse maladies including paralysis, was invented by Cosmas and Damian.

Emperor Diocletian issued a series of edicts that condemned the Christians in his attempt to wipe out Christianity from his empire. During the persecution under Diocletian, Cosmas and Damian were arrested by order of the Prefect of Cilicia, Lysias, who ordered them under torture to recant. However, according to legend, they stayed true to their faith, enduring being hung on a cross, stoned and shot by arrows and finally suffered execution by beheading. Anthimus, Leontius and Euprepius, their younger brothers, who were inseparable from them throughout life, shared in their martyrdom.

The veneration of Cosmas and Damian quickly spread beyond Constantinople; accounts of their martyrdom were rewritten by various authors such as Andrew of Crete, Peter of Argos, Theodore II Laskaris, and a certain Maximus around 1300. The legends are preserved also in Syriac, Coptic, Georgian, Armenian, and Latin.

As early as the 4th century, churches dedicated to the twin saints were established at Jerusalem, in Egypt and in Mesopotamia. Devotion to the two saints spread rapidly in both East and West.

Saints Cosmas and Damian are regarded as the patrons of physicians, surgeons, and pharmacists and are sometimes represented with medical emblems. They are also regarded as the patron saints of twins.

Other Saints of the Day
1. Saint Colman of Elo
2. Saint John of Meda
3. Saint Louis Tezza
4. Saint Justina of Antioch
5. Saint Cyprian of Antioch