Saints Cosmas and Damian were born sometime during the 200s AD in Arabia. Not much is known of their early lives but it is traditionally accepted that they were twin brothers and physicians who practiced their profession near Aegeae in the Roman province of Syria. They used their skills to help the poor in the towns that came, accepting no payment and so were given the titles "silverless and unmercenaries (Ανάργυροι).
When the Diocletian persecutions began, both brothers were arrested by Lysias, the Prefect of Cilicia. The two brothers were subjected to merciless torture and told it could end as soon as the brothers recounted their faith and acknowledged the Roman gods. Tradition holds they were hung on a cross, stoned, shot by arrows and finally executed by beheading. Their three younger brothers likewise were martyred. Their deaths were recorded in 303AD.
By the time of the late 4th century, churches dedicated to the two brothers were established in Jerusalem, Egypt and Mesopotamia. Their feast day was originally declared on September 27th, but was moved to the 26th in 1969 to make room for Saint Vincent de Paul. Both brothers are regarded as the patron saints of Physicians, surgeons, and pharmacists. In the Communicantes they are invoked:
"In communion with the whole Church, they venerate above all others the memory of the glorious ever-virgin Mary, Mother of our God and Lord, Jesus Christ, then of blessed Joseph, husband of the Virgin, your blessed Apostles and Martyrs, Peter and Paul, Andrew, James, ...John and Paul, Cosmas and Damian and all your Saints: grant through their merits and prayers that in all things we may be defended by the help of your protection."
The brothers are regarded as protectors of children in Brazil. In Rio de Janerio, on the 27th of September each year, children are given bags of candy with pictures of the two Saints on them. Another ritual involves giving food to seven children that are no more than seven years old and having them feast while sitting on the floor. Once the children are done eating, the rest of the guests are allowed to enjoy the feast.
In Utica New York, there is a large pilgrimage on the last weekend of September to honor the saints. The 2-day festival includes music, Italian food, masses and processions and is considered one of the largest festivals for Saints in the Northern parts of America.
The Eastern Orthodox Church, Eastern Catholic Church and Oriental Orthodox Church venerate them as Unmercenary Physicians and is a title given only to a small number of saints who heal others out of love of God. This veneration and title comes from the command of Jesus in Matthew 10:8 :
"Freely have you received, freely give."