Marriage Charter of Empress Theophanu

It serves as an example of Ottonian Renaissance art, and the calligraphy of the manuscript has led it to be regarded as one of the most beautiful diplomatic documents of the Middle Ages. In 2005, the document was proposed for inclusion in the Memory of the World Register, but was not included.

Historical context

After the fall of the Western Roman Empire, the Eastern Roman Empire (in modern times also called the Byzantine Empire) remained the surviving continuation of the Roman Empire in its eastern provinces. Charlemagne's imperial coronation in 800 put strain on Western relations with the Byzantine Empire ruled from Constantinople. When Otto I became emperor in February 962, there was contention between him and the Byzantine Empire, and this issue revived in 967 between Otto and Nikephoros II Phokas over the dominion of Italy. On 25 December 967, Pope John XIII anointed Otto II as Otto I's co-emperor.

In autumn 968, battles between the Holy Roman Empire and the Byzantine Empire commenced in the Principality of Capua, in the Duchy of Benevento and Apulia, and hostilities continued until 970. Both sides of the conflict made many attempts to find a diplomatic solution. Otto I intended to receive recognition of his title in Byzantium, and to clarify the borders of Western and Eastern allegiances in southern Italy. He wanted this agreement to be ratified by the marriage of his son, Otto II, to a member of the Byzantine imperial family. Anna, daughter of the deceased Emperor Romanos II, was considered a possible bride. However, Emperor Nikephoros II Phokas was unwilling to marry off a purple-born princess (i.e. a child born to a reigning emperor). After tough negotiations with Nikephoros II Phokas' successor John I Tzimiskes, Archbishop of Cologne Gero secured the marriage of Otto II with Theophanu, a member of the Byzantine imperial family who was not, however, born to the purple.

The Marriage Charter acts as the reference document for the wedding of the 17-year-old Otto II and the 12-year-old Theophanu. The wedding took place on 14 April 972 in St. Peter's Basilica and was officiated by Pope John XIII. Politically, the marriage marked the recognition of the Ottonian Empire by the Byzantine Empire. In this document, Otto II granted Theophanu the right to an extensive dower for personal use throughout her life (legitima dos), as well as her entry into a consortium imperii with Otto II, meaning that both would share imperial authority over the Holy Roman Empire.

It is likely that Theophanu kept the document until the eve of her journey to Italy in October 989, at which time it is believed she placed it in Gandersheim Abbey for preservation. It was discovered and published in 1700 by writer and historian Johann Georg Leuckfeld. Gottfried Wilhelm Leibniz was among the first to recognise the historical significance of this document, and reports on it in History of Welf. After the secularisation of Gandersheim Abbey in 1811, the document was transferred to the Göttingen State and University Library. On 4 May 1820, the archives from the abbey were delivered to the treasury of the duchy of Brunswick. In 1835, the document was transferred to the State Archives of Wolfenbüttel, where it remains.

This document outlines the revenue and profits that Theophanu would receive from this marriage, and it begins with a speech similar to sermons held at weddings. The document describes what Theophanu will receive from Otto II: rights to the revenues from Istria, Pescara; Walcheren, Wichelen, Nivelles Abbey with 14000 belonging farms; and farms in Boppard, Tiel, Herford, Kyffhaeuser, and Nordhausen.