Baring-Gould’s sources: Roman Martyrology; also the ancient one of S. Jerome. In the Anglican Martyrology of Richard Wilson (1608) on Feb. 24th. Authority:—The genuine Acts; of these there are two editions; one, the most ancient, given by Bollandus, terse and short; the other, by Ruinart, longer.
Serenus was by birth a Greek. He quitted estate, friends, and country to serve God in an ascetic life. Coming with this design to Sirmium, the modern Sirmisch, or Mitrowitz, in Hungary, he there bought a garden, which he cultivated with his own hands, and lived on the fruits and herbs it produced. When persecution broke out, he hid himself for some months, but, on its abatement, he returned to his garden. One day there came thither a woman to walk. Serenus, knowing that she had come there to meet a lover, gravely rebuked her, saying, "A lady of your quality ought not to walk here at unseasonable hours, and this, you know, is an hour you ought to be at home. Let me advise you to withdraw, and be more regular in your hours and conduct for the future, as decency requires, in persons of your sex and condition." It was usual for the Romans to repose themselves at noon, as it is still the custom in Italy. The woman, stung at our saint's remonstrance, retired in confusion, but resolved on revenging the supposed affront. She accordingly wrote to her husband, who belonged to the guards of the Emperor Maximian [Diocletian’s co-emperor in the West, 286–305], to complain of Serenus as having insulted her. Her husband, on receiving her letter, went to the emperor to demand justice, and said, "Whilst we are waiting on your Majesty's person, our wives in distant countries are insulted." Whereupon the emperor gave him a letter to the governor of the province, to enable him to obtain satisfaction. With this letter he set out for Sirmium, and presented it to the governor, conjuring him, in the name of the emperor his master, to revenge the affront offered to him, in the person of his wife, during his absence. "And who is that insolent man," said the magistrate, "who has dared to insult such a gentleman's wife?" "It is," said he, "a vulgar fellow, one Serenus, a gardener." The governor ordered him to be immediately brought before him, and asked him his name. "It is Serenus," said he. The judge said, "Of what profession are you?" He answered, "I am a gardener." The governor said, "How durst you affront the wife of this officer in your garden?" Serenus: "I never insulted any woman, to my knowledge, in my life; but, I remember that, some time ago, a lady came into my garden at an unseasonable hour, with the design, as she pretended, of taking a walk; and I own I took the liberty to tell her it was against decency for one of her sex and quality to be abroad at such an hour." This plea of Serenus having put the officer to the blush for his wife's conduct, he dropped his prosecution against the gardener and withdrew.
But the governor's suspicions were roused, and he determined to convince himself whether this gardener were a Christian or not. He, therefore, said, "What is your religion?" Serenus at once replied, "I am a Christian." Then, said the magistrate, "Where have you been lurking, that you have not sacrificed to the gods?" The gardener replied, "God reserved me till this day. Now he calls me, and I am ready to magnify his name, that I may inherit his kingdom." Then the governor ordered him to be executed with the sword.
Relics at Billome, in Auvergne. The feast of his translation is observed in the diocese of Clermont, on May 10th.
In art, S. Serenus is represented with a sword in his hand.