The current city of Trier (in German Trier) was founded around the year 16 BC. as Augusta Treverorum . It is located on the right bank of the Moselle River, in the German state of Rhineland-Palatinate and about 9 kilometers from the border with Luxembourg.
Emperor Augustus made it the capital of the province of Gaul Belgium, and during the late empire it reached such importance that it was known as the second Rome . Constantine fixed his court there when he was appointed Augustus in 305 AD. It houses numerous remains of Roman constructions, three baths, an amphitheater and a basilica. Among them is also the Porta Nigra.
It is a monumental gate that was part of the city walls, on its north side. Until not long ago it was thought that its construction, like the walls, responded to the increase in German attacks during the 3rd century AD.
Today it is known, thanks to the analysis of remains of wood, that the construction of the Porta Nigra began during the reign of Emperor Marcus Aurelius, in 170 AD, although it was never completed.
The consensus among researchers considers it a city beautification project rather than for defensive purposes, which was left unfinished due to financial constraints. Thus, although the holes for the hinges of the doors are present, the projections of the unfinished ashlars continue to protrude in the axis of rotation of the doors, so a mobile door could never be installed.
Some 7,200 stone blocks were used in its construction, the largest of which weigh up to 6 tons. It presents signs and symbols engraved on many of the stones, with the curiosity that a large number of them are upside down. It is believed that they are stonemason's marks, similar to those used later by these professionals in medieval times.
The marks and signs that are in the west tower have dates, but not the year, something that prevented the exact dating of the door. However, they serve to determine the time that was used in its construction. Extrapolating these times to the entire structure, it is estimated that it could be erected in a period of two to four years.
It is unknown what the Romans called it, appearing the name Porta Nigra (Black Gate) for the first time in the Gesta Treverorum of the twelfth century. It was probably known that way due to the dark coloration that the sandstone with which it was made took on.
Both the gate and other Roman constructions in the city were practically abandoned once Roman rule over the area disappeared in the 5th century AD. Little by little many buildings were dismantled to obtain and reuse building materials.
In the Porta Nigra itself, large holes can be seen left by ripping out the iron clamps and lead pieces used during construction. In general traces of this destruction are still clearly visible on the north side.
But around the year 1028 the Archbishop of Trier, Poppo von Babenberg, wanted to make a pilgrimage to the Holy Land. For this he hired a Sicilian monk of a Byzantine father who from the Monastery of Santa Catalina in Egypt dedicated himself to accompanying pilgrims serving as a guide. His name was Simeon of Syracuse.
Simeon led Poppo to Jerusalem, but then decided that he did not want to return to his monastery in Egypt, and instead returned with Poppo to Trier. They arrived in the year 1030 and Simeon asked the archbishop if he would let him live as a hermit in the Porta Nigra.
Poppo accepted and organized a ceremony on November 29, 1030 before all the clergy and people of Trier. At the end, Simeon was locked in a cell at the top of the gate tower, from which he would never leave.
He died there five years later, on June 1, 1035, and was buried in a sepulcher in his own cell. An internal staircase was built so that pilgrims could climb to venerate the relics of Saint Simeon.
The archbishop converted the Porta Nigra into a church, work on which began in 1041, adding an entire surrounding structure. This protected the building to a certain extent from being dismantled to be used as a quarry, like so many others during the Middle Ages. However, in the process the upper floor of the eastern tower was demolished. Next to the church, the current Simeonstift Municipal Museum was built.
The Porta Nigra functioned as a church until October 1804, when Napoleon visited the city and ordered all medieval additions to be removed, restoring the building's Roman appearance. Simeon's tomb and his relics were transferred to the church of San Gervasio and, later in 1971, to the new church of San Simeon.
Demolition works on the medieval structure were completed in 1817. Only the lower part of the medieval apse remained standing for reasons of conservation of the monument. The Porta Nigra was reopened as a city gate on May 22, 1822. In 1876 most of the wall (in which the gate was integrated) and all other medieval city gates were demolished.
Although Simeon's remains are no longer in the Porta Nigra, the Simeonsklause can still be accessed , the room in which, according to tradition, the saint was walled in and lived until his death, in all probability without knowing that he inhabited a pagan building.