Saint Sebastian (c. AD 256 – 288) was an early Christian saint and martyr. His feast day is celebrated on January 20th.
Little is known about the early life of the Saint, but according to tradition, he was born in southern France and educated in Milan. He eventually became a soldier in the Roman army but he hid his Christian beliefs. When he was discovered, he was tied to a post/tree and shot with arrows, though this did not kill him. Saint Irene of Rome took the Saint away and nursed him back to health. After his recovery he went to the Emperor Diocletian to denounce his cruelty in the persecution of Christians. As a consequence, he was beaten to death. His veneration seems to have been occurring as early as the 4th century where writings indicate that Saint Ambrose, bishop of Milan spoke of him in his sermons.
Saint Sebastian has historically been regarded as a saint with a special ability to intercede to protect from plague. Per https://www.catholic.org, the Saint defended the city of Rome against the plague in 680. His association with plague seems to derive from the pagan belief that pestilence was delivered by arrows shot by the gods above. This arrow symbolism is present in depictions of Saint Sebastian, as well as in artwork of the Renaissance where plague victims are painted with black arrows in their body.
Saint Sebastian is also known to be a patron of soldiers and athletes because of his physical endurance.
The Saint is popular across the world, and particularly with Catholics in Kerala, India where the annual feast day is celebrated with lots of color and the pageantry of decorations, processions, and fireworks. Numerous churches and shrines in Kerala and other parts of South India bear the name of the Saint; and in nearly every South Indian church, one will find a statue of the wounded martyr tied to a post/tree with his right arm over his head, and the left tied behind his back.