Serenus the Gardener was a 4th-century martyr who lived in Sirmium, located in the Roman province of Pannonia. Born in Greece, he reportedly moved to Sirmium to pursue a life of celibacy, prayer, and penance. He supported himself through gardening, earning a reputation for his horticultural expertise. His life ended when he was executed for his Christian faith after a dispute involving a local guard's wife led to his interrogation by the governor.