Double Basilica (326-346)
Trier's palace to cathedral transformation
It is uncertain whether the origins of the Helena-tradition date back as far as the first quarter of the fourth century. If it does, we can wonder whether this tradition goes back to the elder Helena. It seems reasonable to assume that the frescoes were made for the occasion of the wedding of Crispus and [the younger] Helena. The attributes on the frescoes refer to married life, as do the putti. The marriage took place c.321. Hardly anything is known about the younger Helena, except that she was married to Crispus, bore him a child in 322 and was probably with child in 324. The man with the scroll may also be connected with Crispus (and [the younger] Helena); he is identified as Lactantius, Crispus' teacher. A suitable place for paintings referring to the happiness of married life is naturally the bedroom, the cubile. It therefore seems plausible to consider the frescoed room not as the cubile of the elder Helena, as Kempf suggests, but as that of the younger Helena. This bedroom was part of the great complex of imperial quarters in which the Caesar Crispus and his wife Helena lived. In 326, after Crispus' execution and damnatio memoriae, the quarters, including the cubile, were demolished; then Trier's cathedral was built on the remains. Although very little is known about the younger Helena, it is not impossible that her cubile and domus were known among the inhabitants of Trier as the cubile and domus of Helena, as we find in the medieval texts. The younger Helena soon disappeared into oblivion, and the cubile and domus were soon considered to have been those of the much more famous elder Helena. The latter was a renowned and indeed legendary figure because of her alleged discovery of Christ's Cross. Moreover, her name was often mentioned in connection with the foundation of churches. Both Helenas may possibly have become confused, which might explain why in the Middle Ages the origin of the Helena-tradition at Trier is dated back to the elder Helena. It may in fact have been the figure of the younger Helena which lay at its roots. For this reason various medieval vitae may attribute Helena's descent to an illustrious family in Trier. Perhaps the younger Helena, about whose origin nothing is mentioned in the sources, came from a rich and distinguished family in Trier? Maybe Crispus, who resided in Trier from 316 onwards, had met her in this northern capital. Her relatively ignoble descent -- the local aristocracy of Trier -- and hence her obscurity, could clarify why, even while Crispus was still alive, the younger Helena is not mentioned in the ancient historiography of the Constantinian period.
Jan Willem Drijvers, Helena Augusta: the mother of Constantine the Great and the legend of her finding the true cross (New York: E.J. Brill, 1992), p. 28-29.
Trier's cathedral, dedicated to St Peter, has a long history which ultimately reaches back to the time of Constantine. Our mediaeval sources report that Helena donated her "house" in Trier, so that it might become a church, and that Bishop Agritius of Trier dedicated this church. The mediaeval sources which offer this statement are generally not very reliable, and it is known that the cathedral was not completed until many years after Helena had left Trier and also some years after Bishop Agritius had died. It is not surprising, therefore, that in the past scholars have denied that Helena had anything to do with the beginnings of Trier's cathedral. But archaeological excavations underneath the nave of the cathedral in 1945-6 and again in 1965-8 have dramatically changed that view. These excavations revealed a room, measuring c. 10 x 7 m, which had been built after 316, but was torn down after 330. The location, the date of construction and the quality of the decorations have persuaded investigators that this room was once part of the imperial residence, "Helena's house," and that it was taken down to make room for the Constantinian church. The painted ceiling of the room was found in situ but in thousands of fragments. The fifteen panels which made up this ceiling have been painstakingly restored and are exhibited in Trier's diocesan museum. Four of these fifteen panels depict richly dressed and bejewelled ladies, who represent either members of the imperial family or allegorical figures. If the former interpretation be right, the four ladies would be Constantine's mother Helena, his wife Fausta, his half-sister Constantia, and the wife of his son Crispus, also named Helena. This writer is persuaded that the latter interpretation is the correct one.
Hans A. Pohlsander, The Emperor Constantine (New York: Routledge, 1996), pp. 17-18.
The Cathedral precincts still enclose a large and well preserved part of the ancient Roman building, dating from the 4th century. Even at this early date - building had begun in 326 - the enormous and impressive structure was built as a full-scale Cathedral with its foundations on the site of a former palace of the Constantine period.
Towards the end of the 4th century, gates led into a cloistered courtyard and further on, into a three-naved Basilica roughly the size of the present-day Romanesque west-facade, and finally into the rectangular central building, dating from about 380 A.D. Its ancient masonry of red sandstone, interspersed with layers of bricks is still clearly identifiable in the Cathedral's north and south walls. Destroyed and rebuilt, modified and enlarged all the time, the Cathedral was repaired and secured from 1964 to 1974, and thus completely overhauled after the destructions of World War II.
Until today, the Cathedral and the Church of Our Lady, near the Great market, represent one of the largest dual church buildings of early Christian architecture.