Cosmas and Damian were twin brothers born in Arabia who studied medicine in Syria. They became physicians of unusual skill and made it a rule never to accept payment for their services — earning them the Greek title 'Anargyroi' (the Holy Unmercenaries). They treated both Christians and pagans, refusing fees from both.
During the persecution of Diocletian, both were arrested at Aegeae in Cilicia (modern Cyprus area) and brought before the prefect Lysias. They were subjected to multiple tortures — crucifixion failed (the nails fell out), stoning failed (the stones turned back on the executioners), and finally beheading succeeded around 287.
Their cult spread rapidly. Pope Felix IV (526–530) built the Basilica of Sts. Cosmas and Damian in the Roman Forum, the first Christian church to occupy a building of the imperial Forum itself. The mosaic of Christ above the apse — Christ presenting Cosmas and Damian as flanking saints — is one of the supreme masterpieces of late antique Christian art. They are named in the Roman Canon of the Mass.