Strasbourg Oaths

The Oaths were sworn on 14 February 842 at Strasbourg, following the disintegration of the Carolingian Empire after the death of Louis the Pious. Charles the Bald and Louis the German, sons of Louis the Pious, allied against their elder brother Lothair I, who claimed imperial supremacy. The alliance was a strategic move in the civil war that culminated in the Treaty of Verdun (843), which partitioned the empire into three kingdoms.

The ceremony was recorded by Nithard, a Frankish historian and grandson of Charlemagne, in his Histories (De dissensionibus filiorum Ludovici Pii). Nithard’s account is the sole contemporary source for the event, and his manuscript, now in the Bibliothèque nationale de France (MS lat. 9768), is the only witness to the oaths’ text.

The Oaths are the earliest connected text in a Romance language that is recognizably French, and the earliest in Old High German. The Romance text, spoken by Louis the German so that Charles’s troops could understand, is written in a language that already shows features distinct from Latin, such as the use of pro for pro and the future tense salvarai (from Latin salvare habeo). The Germanic text, spoken by Charles the Bald for Louis’s troops, is in a Rhenish Franconian dialect, showing early High German consonant shifts.

Philologists have debated the exact dialectal classification of the Romance text, with some arguing it is a northern French or Picard variety, while others see it as a lingua franca of the Carolingian court. The Oaths are thus a cornerstone for the study of the transition from Latin to the vernacular languages of Europe.

The Oaths consist of two parts: a mutual promise of alliance and a protective oath to each other’s troops. The text is formulaic, with each brother swearing to aid the other against Lothair, and to never make a separate peace. The Romance version begins Pro Deo amur et pro christian poblo et nostro commun salvament (For the love of God and for the Christian people and our common salvation), and the Germanic version begins In Godes minna indi in thes christanes folches indi unser bedhero gealtnissi.

The oaths were sworn in the presence of the assembled armies, and the use of the vernacular was a deliberate political act to ensure that the soldiers could understand the promises. The text also includes a clause that each brother would not knowingly do anything that would harm the other, and that if either broke the oath, the other would be free from his own obligations.

One lesser-known detail is that the Oaths were not the first vernacular document in Europe; earlier Germanic legal texts exist, but none are as long or as well-dated. The Oaths are also unique in that they are a bilingual text, with the Romance and Germanic versions not being exact translations of each other, but rather adapted to the respective audiences.

The manuscript itself has a complex history: it was copied in the 10th or 11th century, and was part of the library of Saint-Médard de Soissons before entering the royal library. The text was first published in 1588 by the French scholar Pierre Pithou, who recognized its linguistic importance. In the 19th century, the Oaths became a symbol of Franco-German reconciliation, and were cited by historians such as Jules Michelet and Jacob Grimm. The exact pronunciation of the Romance text has been reconstructed by historical linguists, and it is often recited at academic ceremonies.

Carolingian Empire

The Frankish realm ruled by the Carolingian dynasty, covering much of Western Europe from the 8th to 10th centuries.

Old High German

The earliest stage of the German language, spoken from around 500 to 1050 AD.

Rhenish Franconian

A dialect group of West Central German, spoken in the Rhineland.

Treaty of Verdun

The 843 treaty that divided the Carolingian Empire among the three surviving sons of Louis the Pious.