A sermon from the 13th century for the Exaltation of the Holy Cross. (The Latin text is at the link.)
From Canticum Salmonis
The root of Jesse shall stand for an ensign of the people. Jesse was father to David the king, from whose seed Christ descended. This root of Jesse was Christ according to his divinity; the twig that sprouted from Jesse was Christ born according to his humanity. It standeth for an ensign of the people, because the Holy Cross of Christ’s Passion and our redemption is an ensign for the entire Christian people. This is the ensign gainsaid by Jews and paynim, but it blesses the multitude of the faithful and every creature of the sacraments, and vanquishes all adversity. This Holy Cross is venerated by the angels and adored by men. Verily, by the cross the devil is made captive, the world is liberated, hell is despoiled, paradise is gladdened, and the Christian people around the globe are invited into the heavenly kingdom.
The heavenly fatherland exults in the triumph of the holy Cross, the Church rejoices, and Jewish perfidy wastes away. The victory of the holy Cross subjugates death and strips it of its dreadful tyranny. The Holy Cross has become for us the key to heaven, the powerful destruction of Hell. Sanctified by Christ’s body and blood, it is most worthy to be honored by all the faithful. It protects sinners, governs the saints, fosters little ones, makes hale those worn down by age, lifts up the fallen, guides the just, reforms the unjust, and lends assistance to all who show it faithful reverence. On account of the wood, our first parent plunged into the open main of this world as it were into a ship-wrecking whirlpool, and the ravenous Leviathan swallowed the whole human race—a cruel death! Then did our Redeemer raise the standard of the Holy Cross and tie up the foe’s scaly maws with the hook of his flesh, so that pierced with the point of the life-giving wood, that vile beast of prey vomited up those he had gulped because of the forbidden wood. This Holy Cross is our lamp of eternal light in the darkness of this life, leading those who follow it into heaven, and granting those who love it angelic joys.
Heaven has often made known the virtue of his Holy Cross in wondrous ways.
In a town there was a certain Christian who owned a figure of the Holy Cross. When he died, a Jew came into possession of his house. One day he invited his co-religionists to a banquet, not knowing that there was a crucifix in the house. Now when in the midst of feasting they espied the image of the Holy Cross, they arose with a mad shout and seized the crucifix. “We have heard,” they said, “that our fathers flogged Jesus; we too ought to disgrace his image with floggings.” Howling these words, the faithless Jews inflicted beatings upon the crucifix and—wonder of wonders!—their blows drew out drops of blood. Jeering at this wonder in their delirium, they said that Jesus was wounded by their ancestors, so likewise his image should suffer at their hands. And so they stabbed and poked holes in it with their knives, but to Christ’s glory streams of blood flowed out. After word of the affair got out, a throng of cripples rushed to the spot, gathered the dripping blood in vessels, and smeared it on their disabled limbs. O what wondrous miracles of Jesus Christ were worked through images of the Holy Cross! Instantly the blind rejoiced to regain their sight, the deaf celebrated their restored hearing, the mute shouted for joy, the lame jumped for joy, and all the crippled celebrated their wholeness. The Jews shouted Christ’s praises in a loud voice, forthwith became believers and were baptized, and venerated the Holy Cross with the highest honor.
Once upon a time, a Jew was travelling to Rome. As night overtook him, he retired for repose to an abandoned pagan temple by the road, but was so afraid of that place of horror that he signed himself with the Holy Cross. At about midnight a crowd of demons arrived, one of whom was seated on a high chair like a king. He inquired of the others what villainy each had done that day. As they were telling of their mischief, one leapt into the middle to report that he had induced the bishop Andrew, a man of perfect religion, to fall in love with a nun; he had drawn him so far forth that, late at night as the bishop left her, he had given her a merry spank on the back end. As all present shouted their approval and praised his industry, and urged him to bring to completion the job he had begun, the Prince of Evil ordered them to inquire who had dared presume to take shelter in his house. His wicked retainers hastened to the Jew and squinted intently at him. They wondered, saying, “Look, here is an empty vessel, but yet it is signed!” Hearing this, all the evil spirits vanished because they could not bear the name of the Holy Cross. The Jew rose up and came to the bishop at that very hour and told him all that he had seen. The bishop fell prostrate upon the earth and praised God for keeping him from sin, baptized the believing Jew, and shortly thereafter ordained him a priest. The temple wherein the demons had gathered he made into a church dedicated to St. Andrew the Apostle. And so both men whom the devil boasted to have in his power were saved by the virtue of the Cross.
But just as the Cross restores the predestined to life, so it throttles the reprobate. Julian the Apostate, for instance, wanted to learn the magic arts while still a boy, and for that purpose dwelled with a sorcerer in a solitary house. When Julian left the house, he began to invoke demons, but seized with terror at their sight he signed himself with the Holy Cross. Seeing this, the demons fled, leaving the frightened wretch alone. The sorcerer came in and asked him if he had seen anything. Julian replied that he had seen hideous Ethiopians, but they disappeared after he made the sign of the Cross. The sorcerer told him the demons were displeased by this sign and hence withdrew from his presence. On this account the unhappy Julian began to loathe the Lord’s Cross with such hate that he started to detest and abhor the entire Christian religion with his whole heart, and once he became emperor he enforced paganism throughout the globe, striving with all his might to erase the Christian name from the earth. Behold how the Cross, which is the source of salvation for all, became for Julian a pit of death.
On the other hand, by the Cross was Cyprian saved, who had been predestined for eternal life since before all ages. This famous sorcerer, who had driven scores of people mad with his magic arts, performed a multitude of heinous crimes, and riven open a great many pregnant women with spells and sacrificed their babies to demons, came to the way of salvation through the virtue of the Holy Cross in the following manner:
There was a young maid named Justina, beloved of God, whom this sorcerer tried to persuade to consent to his lust. He cast a spirit of fornication into her, but she repulsed it by making the sign of the Holy Cross. When Cyprian questioned the spirit why he had not led the maiden unto him, he said that he had seen a frightful sign and fled from her forthwith. Jeering at him, the sorcerer sent a stronger spirit, whom fear of the Cross likewise put to flight. When Cyprian asked why he had not brought the virgin, he answered that he could not do so on account of some frightful sign. He then undertook to dispatch the prince of demons, who shifted into a woman’s shape, and solicited the maiden with smooth words and fiery darts. As soon as she made the sign of the cross, the evil one vanished like smoke and went back in confusion to the sorcerer, reporting how he had fled from some terrible sign. When Cyprian asked what sign it might be that had undone all their might, the devil replied that Christ’s Cross had sapped all their power and triumphed over all their devilish arts. Hearing this, Cyprian spurned the devil, converted to Christ, and as a perfect example of the Christian religion was raised to be a bishop and noble doctor of the Church, and alongside the same Justina offered himself in the face of divers torments as a living host to God and become a glorious martyr. And thus, with the Cross as their standard, the elect bear home the trophy.
My brethren, you should know what today’s feast is about. Chosroës, king of the Persians, ravaged Judæa and bore off the Holy Cross from Jerusalem unto his own land. There he built a silver tower as a sort of heaven, installing within images of the sun, moon, and stars. This tower was so contrived that it could be moved, and it made a sound like the rumble of thunder. Water too was pumped up through hidden pipes and then came down again like showers into several caverns inside. He hung the Cross up in the tower at his right hand, for his son; to his left he placed a bronze cock that stood for the Holy Spirit, while he sat on a throne in the middle and ordered himself to be worshiped as God the Father. Heraclius, emperor of the Romans, came against him with an army, and Chosroës’ son hastened to meet him at the Danube with a strong force. The people agreed that the princes should engage in a duel on the bridge, and that all should submit to the victor. So it happened, and Heraclius emerged victorious, and the whole army obeyed him. Once he had subjugated Chosroës’ realm, Heraclius climbed up into Chosroës’ “heaven” with a few others, found the tyrant on his throne, asked him if he wished to be baptized, and when he refused, cut off his head. He ordered his son, still a boy, and his whole army to be baptized. He raised the child from the font himself and put him on his father’s throne, giving him command of the kingdom, and then hastened joyfully back to Jerusalem with the Holy Cross. He rode in from the Mount of Olives under the imperial insignia, riding a caparisoned horse, but the city gate before him was blocked off by an attached wall. And behold the Holy Cross shone in the heavens with a blinding light, held above the gate by an angel of the Lord who said, “When the King of Heaven entered these doors on the way to his Passion, he did not flaunt purple cloth or crowns, and was borne on the back not of a haughty steed, but of an ordinary ass.” Thus spoke angel, and disappeared into heaven. The emperor, therefore, removed his ornaments and took up the Cross, resounding a hymn to the Lord with the entire people. Anon the door opened up for him, and the Holy Cross was venerably exalted in the place prepared for it. On the same day, through the glorious Cross a dead man was restored to life, four men with the palsy recovered their health, ten lepers became well, fifteen blind men gained sight, many were freed from demons, and a great number were cured of various diseases. Moreover, as soon as the Cross was carried away from Chosroës’ temple, an exceedingly sweet smell wafted from that province, suffusing the breasts of everyone in Jerusalem.
Also today Cornelius, bishop of the Romans, and Cyprian, prelate of the Church of Carthage, shed their blood for their sheep and entered the heavenly realm to receive their crowns.
Now, my beloved, lift high the Holy Cross with your praises and shower your prayers upon these holy men, that he who redeemed you by the Cross and made you co-heirs of the Kingdom by his Blood, may grant you to triumph over the world through the standard of the Holy Cross and exult forever with the saints in the heavenly Jerusalem, where eye hath not seen, &c.
 Isaias 11:10
 The Stirps Jesse (“Jesse Tree”) was a new artistic motif when Honorius wrote.
 The following exemplum is based on Gregory the Great’s story of Bishop Andrew of Fundi, told in Dialogues 3.7. Gregory’s story makes no mention of the Jew being ordained a priest.
 From the Canticle of Moses, Deuteronomy 32:10.
 On the history of this legend, see Companion to Literary Myths, Heroes and Archetypes.
 The story of Cyprian and Justina was first told by St. Gregory Nazienzen and Prudentius in the 4th century, when St. Cyprian of Carthage has already been conflated with a Cyprian the Magician, converted by then killed with the maiden Justina in the Diocletian persecution. Usuard has only a short entry on the two on 26th September, and does not conflate them, and Rhabanus Maurus does not tell the extended version.
 The story is a summary of the entry for September 14th in Usuard‘s Martyrology (PL 123:356c), itself drawn perhaps from Rhabanus Maurus’ 70th homily, Reversio sanctae atque gloriosissimae crucis Domini nostri Jesu Christi, the earliest evidence for the reception of this legend in the West (Homilia LXX, PL 11:131-134). Neither source mentions the effigy of a dove or makes Chosroës’ blasphemous celestial diorama into a temple of the Trinity; this may be Honorius’s own pen. It later reappears in Sicard of Cremona’s Mitrale and John Beleth’s Summa de ecclesiasticis officiis, as well as in the Legenda aurea. For more on the legend, see A Heritage of Holy Wood: The Legend of the True Cross in Text and Image.
 Usuard and Rhabanus Maurus read argenteam (“silver”), and most MSS follow them, but Admont, Benediktinerstift, cod. 131 gives ęream (“bronze”), a reading supported by a Kaiserchronik composed in Regensburg ca. 1150, which mentions Chosroës making a “heaven of bronze.”