There must have been a time when people were so fascinated by the wood of Christ’s cross that the longing to see it, to touch it, even to kiss it consumed them completely. It was the time when Christianity had cautiously begun to emerge from its struggle for recognition and the religion’s expansion was outwardly manifested in new places of worship from Rome to Constantinople, from Jerusalem to Edessa. And it was at that time, so it is told, that a single Jew and a Christian queen dug deep into the earth and found that which people yearned to find: the True Cross.

The research of the legend of the True Cross encompasses relic cults, pilgrimages, travelers' tales, and the Tree of Life; it involves Church Fathers, crusader kings, Teutonic Knights, and mendicant orders, all of which influenced the legend's depiction from its earliest representation in manuscripts, reliquaries, and altarpieces, to the great monumental cycles of the high Middle Ages. If the holy wood were the medium of medieval memory, the Legend of the True Cross reveals the growth rings of fifteen centuries of imagery.

In this paper, I want to focus on one peculiar theme. According to the Legend of the True Cross, the Byzantine emperor Heraclius (610-641) was involved in a battle against Chosroes II (588-628?), the Sassanian king who had stolen the cross in Jerusalem. Entering the astrological tower in Ctesiphon, Heraclius finds Chosroes sitting at his mechanical throne. It was kept in constant movement by horses, just as the universe is constantly moving. Into the throne, Chosroes had placed the cross relic "as the sun," and an image of a cock "as the ghost." Chosroes considered himself "as the father." Heraclius decapitates Chosroes on his throne and restitutes the cross to Jerusalem. This event, the Restitutio crucis, is remembered during the so-called feast of the Exultation of the Cross at September 14^th.

I will explore the tradition of the Restitutio crucis in the historical, liturgical, and iconographical sources.

I.

Already in his own lifetime a complex of legends was generated around Heraclius.^[3] He was renowned for his series of victories over the Persians, who threatened the Greek-speaking part of the Roman Empire at the beginning of the seventh century and who, moreover, had plundered the Church of the Holy Sepulcher in Jerusalem. The legend of the Restitution of the Cross is part of a broad cultural platform. Indeed, the figure of Heraclius is shared not only by Persians and Christians but also by Jews and Arabs as well. Because all these different cultures appropriated the stories, the legend developed in an erratic way. The religious-cultural implications of the conflict between the Greeks and the Persians were so profound that they were described in eschatological and apocalyptic terms.

The events had an enormous impact on the Christian empire of that time – and on the "heathen" world beyond. Not only were geographic borders the stake in political shifts but also the various worldviews concerned. In his Expeditio Persica (622) and Heraclias (628), ^[4] Georgios Pisides, deacon of Hagia Sophia in the time of the patriarch Sergius, depicted the events as a horrible nightmare, an apocalyptic peril. Theophanes (765-817, Chronographia) described Heraclius as a mythic hero, who only by his great perseverance had been able to force the empire of Chosroes to yield. ^[5] In an early seventh-century source from Edessa, Heraclius is even compared with Alexander the Great. ^[6] In the same period, Antiochus Stratedus describes the taking of Jerusalem by Chosroes with evangelical references to Christ’s Passion, ^[7] while the anonymous Jewish writer of the Dream of Zerubbabel regards the Sassanian incursions as a Messianic liberation from the "betrayer" Heraclius. ^[8]

Historians suppose that the campaigns of Heraclius took place in the years between 622-628 and that Heraclius did indeed restore the relic of the True Cross (preserved in the Church of the Holy Sepulcher since Helena found it and it was subsequently stolen by the Persians) to its original place in Jerusalem. It was mentioned in both contemporary and near-contemporary sources in the Byzantine world, such as Georgios Pisides’ In Restitutionem S. Crucis. ^[9] In that source, it was said that Patriarch Modestos examined the relic and proclaimed it intact. It was preserved in a sealed container. Of course, it is hard to reconstruct the historical truth from these chronicles to know whether the restitution of a relic of the Cross really took place and how and when. This is not the place to dwell on this; however, historians nowadays agree on the factual restitution of a cross in a great ceremony on 21 March 630. I refer to the recent study by Walter Kaegi (2003). ^[10] An ironic detail occurs in this history: the eastern parts of the empire proved unable to withstand new Persian invasions and the rapid Arab expansion following the death of Muhammad (570-632). ^[11] Heraclius could do little but look on; a few years later, from 634, the areas he had freed from the Persians fell into the hands of the Arab Caliph Omar and subsequently converted to Islam. ^[12] In 635, the Cross he had restored to Jerusalem was brought for safekeeping to Constantinople and was subsequently lost to history. ^[13]

II.

Already in the seventh century the restoration of the Cross was celebrated in Constantinople on 14 September, Holy Cross Day. ^[14] The feast gained a firm foothold in western Europe and became extremely popular due to the eighth-century homily Reversio sanctae atque gloriosissimae cuicis Domini nostri Jesu Christi. The text was edited by Migne under Hrabanus Maurus (780-856), ^[15] archbishop of Mainz (847) and abbot of the monastery school of Fulda, although today this authorship is contested. The Swedish theologian and philologist Stephan Borgehammar is currently preparing the critical edition of the Reversio sanctae crucis for the acta bollandiana and does not believe Hrabanus Maurus was the head of the stemma. ^[16]

The author of the Reversio specifies that the Byzantine emperor beheaded Chosroes II in his tower palace. Chosroes had built a tower in which he installed images of the sun, the moon and the stars for what is called "occult" purposes. As if he were God himself, Chosroes could watch from above how the rain streamed earthwards. Deep in a cellar, horses kept the tower in constant motion, like the heavenly bodies themselves. Chosroes had placed the stolen Cross beside him.

A miniature in the Mont Saint-Michel Sacramentary (ca 1060) is the earliest depiction of the Restitutio (fig. 1). ^[22] The full-page miniature is framed by an acanthus border with a floral roundel midway along each side. In the upper register is Heraclius riding with eight companions. On the tower on the left stands an angel bearing a processional cross which he holds protected with a cloth. The same city appears in the scene below. Firstly Heraclius is depicted full-length, reverently holding the processional cross with a cloth. Then Heraclius is shown again, now barefoot and prostrate on the ground. For that matter, the prostration on the ground, the humilatio, is something that occurs frequently in monastic communities, and walking barefoot alludes to reverence for God, atonement or mourning, poverty and pilgrimage. ^[23] The eighth-century ordines Romani refer to the report of a Frankish monk from Einsiedeln concerning the Good Friday ceremony in Rome. The ordines mention that the procession bearing the relic of the Cross went barefoot from the Lateran to Santa Croce in Gerusalemme. ^[24]

In 1035, Duke Robert journeyed to Jerusalem, after he had donated many possessions to Mont Saint-Michel. According to the chronicle of Robert of Torrigny (1145-1158), the Archangel Michael had appeared to the duke in a dream and required him to make these benefactions (1027 or 1028). ^[25] The founding angel of the Normandy abbey played an important part in the Heraclius story, which might account for the increased interest in this iconographic motif. Also the sacramentary might have particular interest in the Heraclius story referencing that other important conquest of William the Conquerer in 1066. However, the miniature did not become a model.

From the 12^th century onwards, the ages of the crusades, the Exultation iconography becomes widespread and becomes conventional in the liturgical and para-liturgical manuscripts. Exactly in that same period, the reception of that other motif of the legend takes place, the throne or decapitation of Chosroes. ^[26]

III.

In 1878, M. J. Mohl published a German translation of the Firdausi verses written down in present-day Iran in 900 or thereabouts. ^[27] In this legend, a king builds a colossal "Taq dis"; etymologically this means "equal to the firmament" (fornici similis). ^[28] This "celestial throne" was made of the richest materials and embellished with all the signs of the zodiac. Four steps led up to a throne supported by lions. The Persian astrological throne functioned within a ritual context. As the center of the heavenly realm, the ruler was manifested as one who has power to influence the stars. Indeed, the ruler is venerated as the entity into which the cosmic powers have poured. The throne symbolizes this power.

In the Firdausi verses, it is told that Alexander the Great, indifferent to the treasures of the palace and unfamiliar with the astrological potential of the construction, destroyed the dazzling "Taq dis." However, Chosroes II conceived the plan of restoring the ancient astrological temple. T. Nöldeke suggests that the specific passage of the legend in which Chosroes II appears was based on the "Book of Chosroes," a lost Arabic chronicle that goes up to 628 AD. ^[29] Cedrenos (Historiarum compendium, 1057) also supplemented his Elevation of the Cross passage with a description of the astrological temple. ^[30]

The throne of Chosroes corresponds to the planetarium or the cosmic clock. Philostratus described such a structure in Babylon. The men’s hall in the palace had a domed vault that resembled the heavens. The dome was decorated with sapphires and with images of their gods, the planets. ^[31] At the time of early Christianity, planetaria were also made for private purposes. The Stephen martyrology tells of a pagan, Chromatius, who built a cubiculum holovitreum, in quo omnis disciplina stellarum ac mathesis mechanica as a device for healing. Even so, only with the help of Stephen did the sick recover. The pagan destroyed the construction and converted to Christianity. ^[32]

The descriptions in the Reversio homily are analogous. There is mention of many precious metals, of the sun and moon as a quadriga and of machinery kept in motion by horsepower. Persian textiles and precious metalwork still inform us about this sort of throne which was connected with the cult of the sun. Actually the cock was connected with the sun, and more specific with the rising sun. In the Arabic world, the cock is an image of victory and the Last Judgement. ^[33] The Sassanians practiced the alectryonomancia: divination by cocks and omen magic. The quadriga motif may also be an iconographic reminiscence of the heraldically-posed animals (usually bulls or lions) or horses harnessed to the chariot of the sun. ^[34]

In Christendom, the attitude to planetaria depended on the use to which they were put. As a place where the deification of the ruler took place –as they functioned in the East – they were repudiated. As works of art – as mimesis of the universe, thus – they were particularly appreciated by the Pythagorists. Notwithstanding their ambiguous associations, the phenomenon was familiar. In Hrabanus’ homily on the Elevation of the Cross, the cosmic throne acquired an extra function associated with the relic of the Cross, which Chosroes had set up next to his throne (iuxta eam). ^[35] Gotfried of Viterbo (ca. 1125-ca. 1192) added to this that Chosroes hoped the Cross would endow him with power to influence life and death. ^[36] This is a motif that embroiders on Chosroes’ legendary ability to manipulate the heavenly bodies and indicates the foolishness with which Chosroes uses the Cross as a magical object in a nature religion, failing to understand it as the mystery of the Passion. Moreover, in the legend, Chosroes is decapitated as the images of idols are decapitated. In the Middle Ages, the Saracens were the prototype of idolatry. ^[37]

In Chosroes’ cosmic throne, Christians recognized eschatological traditions from the Holy Scriptures and the Apocrypha. In Isaiah 14, 12-15, the fall of the king of Babylon is told: "How you are fallen from heaven, O Day Star, son of Dawn! How you are cut down to the ground, you who laid the nations low! You said in your heart, I will ascend to heaven; I will raise my throne above the stars of God; I will sit on the mount of assembly on the heights of Zaphon: I will ascend to the tops of the clouds, I will make myself like the Most High. But you are brought down to Sheol, to the depths of the Pit." The passage refers to the pride of Lucifer. According to 2 Thessalonians 2, 4: "He opposes and exalts himself above every so-called god or object of worship so that he takes his seat in the temple of God, declaring himself to be God." This pride is personified by the Antichrist. In the legend of the Exultation of the Cross, the figure of Chosroes is modeled on those of Lucifer and the Antichrist.

The eschatological conceptualization of Heraclius and Chosroes appears from the commentary on the Apocalypse written by Alexander of Bremen (Minorite, d. 1271), which is characterized by the search for links between the course of soteriological history and the End of Time. The passages were illustrated in three Latin manuscripts (fig. 2). ^[38] The Minorites were convinced that every event was a prefiguration of this End of Time. In this way, a textual structure was developed in which the Apocalypse is diachronically interwoven with soteriological history. The type of the historically interpreted Apocalypse was not new; it had already been developed in the Apocalypse of Pseudo-Methodius (ca. 655). ^[39] Pseudo-Methodius tells how the Last Emperor lays down his imperial insignia (crown and scepter) on Golgotha, surrendering them to God. ^[40] Alexander of Bremen adopts the same narrative structure in his commentary on Chapters 12 (the pregnant woman and the dragon) and 13 (the two beasts) of the Apocalypse, but he ascribes the roles of the "anonymous" characters of the Last Emperor and the Antichrist to Heraclius and Chosroes, respectively.