Mainz Cathedral or St. Martin's Cathedral (German: Mainzer Dom, Martinsdom or, officially, Der Hohe Dom zu Mainz) is located near the historical center and pedestrianized market square of the city of Mainz, Germany. This 1000-year-old Roman Catholic cathedral is the site of the episcopal see of the Bishop of Mainz.
Mainz Cathedral is predominantly Romanesque in style, but later exterior additions over many centuries have resulted in the appearance of various architectural influences seen today. It comprises three aisles and stands under the patronage of Saint Martin of Tours. The eastern quire is dedicated to Saint Stephen.
The interior of the cathedral houses tombs and funerary monuments of former powerful Electoral-prince-archbishops, or Kurfürst-Erzbischöfe, of the diocese and contains religious works of art spanning a millennium. The cathedral also has a central courtyard and statues of Saint Boniface and The Madonna on its grounds.
During the time of Mainz Archbishop Willigis (975–1011), the city of Mainz flourished economically, and Willigis became one of the most influential politicians of that time, ascending to regent of the empire between 991 and 994. In 975–976 shortly after his installation he ordered the construction of a new cathedral in the pre-Romanesque Ottonian architecture style. This new building was part of his vision of Mainz as the "second Rome".
This new cathedral was to take over the functions of two churches: the old cathedral and St. Alban's, which was the largest church in the area, belonging to a Benedictine abbey and serving as the burial ground for the bishops and other nobles, including Fastrada, a spouse of Charlemagne. Most of the synods and other important meetings were held at St. Alban's Abbey.
The new cathedral consisted of a double chancel with two transepts. The main hall was built in the typical triple-nave "cross" pattern. As was usual at that time no vault was included because of structural difficulties relating to the size of the building. Six towers rose from the church. A cloister was enclosed in the structure and a small freestanding church, St. Mary's Church, connected by a colonnade. This small church developed later into the collegiate church of St. Maria ad Gradus.
Sandstone was used as the primary building material for the cathedral. The inside was plastered white under the Archbishop Bardo, probably in the middle of the 11th century. During renovations ordered by Henry IV in the late 11th century, much of the outside was also plastered, but the cornices were left exposed in their original red and yellow. It is believed that the coloring of the cathedral was changed on a number of occasions, but no further documentation of the coloring is available until records of the Baroque works.
The cathedral suffered extensive damage from a fire on the day of its inauguration in 1009. Archbishop Bardo (Bardo of Oppershofen) presided over the completion of the cathedral begun under Willigis. By 1036 the main portions of the body of Mainz Cathedral were complete. Willigis was buried in the second church he had initiated, St. Stephan's, in 1011.
From the ninth to 12th century, several important churches in the Holy Roman Empire were built with choirs on both ends. One of the first was Cologne Cathedral of 855 ("Hildebold's Cathedral"). One of the oldest preserved examples is St. Michael's Church, Hildesheim, erected since 1010. Gernrode Abbey church was added a second choir, in the 12th century. This type of footplans also was acquired in Poland (Tum Collegiate Church) and Hungary (Pécs Cathedral). The reason for building two chancels is not entirely clear. Many scholars suggest that there is some symbolic significance, such as empire and church, or body and spirit, but no irrefutable evidence for these theories exists. Others claim that the construction has a functional purpose for ceremonial processions. Whatever the original intent of the double chancel, the eastern chancel came to serve as the location for the mass and the western chancel was reserved for the bishop and pontiffs.
In most cathedrals at the time, the main chancel lay on the east side. Willigis, however, designed his cathedral with the main chancel on the west, presumably modeled after the great basilicas in Rome, which were constructed this way. (Willigis's design bore a striking resemblance to Old St. Peter's Basilica.)
The chancel was badly damaged in the fire of 1009, and remained that way under Archbishops Erkanbald and Aribo. The chancel was finally reconstructed under Bardo. He then buried his predecessor Aribo there, before the rest of the cathedral was even finished. (Willigis's remains are not, as sometimes believed, in Mainz Cathedral; he was buried in his second construction project, St. Stephen's.)
In 1081, fire once again struck the cathedral, and the appearance of the Salian western end is not known. In 1100, Henry IV ordered reconstruction in the old Lombardic style. The old flat chancel end on the east side was replaced with a large apse, which external gallery with a narrow arcade supported by short columns crowned the semicircular wall with a wide pseudo arcade and tall pilasters on both sides. The new chancel had a triple-nave crypt. The damaged square tower had been replaced with an octagonal dome, above which an octagonal tower was added later. Flanking stair turrets remained from the first cathedral. These changes closely resembled the renovations Henry had overseen on Speyer Cathedral a few years earlier.
Henry also undertook a few other minor changes, such as raising the transept on the east side and adding openings at the column level. These column-level portals were among the first ever such constructed.
Henry died in 1106, before his intended changes were complete. With his death, the funding for the renovation of the cathedral dried up and so the remaining construction was abandoned. Mainz Cathedral is considered one of the three Kaiserdome ("Emperor's Cathedrals") of the Holy Roman (German) Empire, along with Worms Cathedral and Speyer Cathedral.
Archbishop Adalbert I of Saarbrücken (1110–1137) had a two-story chapel, called the Gotthard Chapel, built as the official palace chapel next to the cathedral. It is believed that he also ordered the renovation of the main body of the cathedral, mainly due to similarities between the main hall and the vault of the new chapel.
Conception for the renovations was again taken from the Romanesque Speyer Cathedral. This time, however, without money from the emperor, the builders lacked the resources to acquire the high-quality sandstone used in Henry's additions. They instead used limestone. The other aspects of the renovations were also much cheaper, and the extravagant style of Speyer Cathedral was largely avoided.
The central nave was built to 28 m (92 ft), 5 m (16 ft) short of Speyer Cathedral's 33 m (108 ft). It seems that the blind arches were intended to encompass the windows, as in Speyer Cathedral, but the height of the roof did not allow this. The resulting three-level effect, due to the arches ending before the windows, was a technique not before seen in architecture.
The main hall was further renovated throughout the entire 12th century. The entire outer wall structure was eventually replaced. Around the year 1200, the ceiling was replaced with a ribbed vault, a rather new technique for the time.