The Pactum Lotharii is a document that was originally written and produced in 840 AD and signed by the Republic of Venice and the Carolingian Empire.Historians over time have not written much about the Pactum Lotharii. However, historians do talk about the Republic of Venice and Carolingian Italy during this time. Historians have agreed that Venice was a powerful city with many strengths in political and commercial aspects and therefore, the treaty worked to clear up several aspects of trade, borders, and military discrepancies between the two powers. The document outlines specific areas of Italy that were given to the Venetians and drew clearer borders of the Republics domain, it also outlined what circumstances the Carolingians could call upon Venetian help in military matters [1] and specific border control issues between people. Because of the power Venice held during the ninth century, it was in poor judgement for a Carolingian conquest to occur, especially as the Carolingian Empire became increasingly characterized as a decaying empire in the time leading up to the Pactum Lotharii and stemming further into history.
Written in Latin, the pact reflects the administrative practices of the Carolingian court and indicates the new Venetian Republic's geographic boundaries from Cavarzere to Grado. It establishes trade agreements, legal requirements, and military cooperation. Additionally, the pact granted Carolingians considerable power over Venice by allowing them to directly interfere with Venetian Politics. Most of the involvement between the Carolingians and Venetians stemmed from Pactum Lotharii, which was updated with each change in ruler.
From a draft translation by Jenny Benham, the Pactum relays information about how the signatories handle refugees, slaves, livestock, trade, naval presence, justice, and more. The pactum describes how people running from the law in Venetia and hiding in Carolingian territory shall be returned to Venetia within sixty days if they are found, and if not, they will give the Venetians five-hundred pieces of gold for every person not returned.[2] If slaves flee, the person who returns them will also receive a piece of gold. Additionally, the Carolingians will not knowingly buy or sell Venetian Christians and if any captives are found, the person responsible will be given to the Venetians along with their property. In terms of assistance, both sides are required to aid in naval duties as requested by Emperor Lothar I. Trade between powers is allowed as long as it maintains a balanced relationship. As for justice, the missi should be prepared to provide justice to both sides so that all can receive his complete justice. If any person were to harm another, on either side, they must pay a certain amount of gold, depending on the weight of the infraction, to make right. In relation to harm, if a person makes another person a eunuch, they themselves must also suffer the same punishment.----The treaty included a commitment on the part of the Venetians to help the empire in its campaign against the Slavic tribes.[3] In return, it guaranteed Venice's neutrality as well as its security from the mainland.[4] However, the treaty did not end the Slavic plunderings since by 846, the Slavs were still recorded menacing cities such as the fortress of Carolea.[5] This underscored the way the pact was more symbolic because it merely reiterated the agreements that had been already made in the past between the two empires. It concerned the rights of land use and administration of justice.
It is also a valuable document that allows to know precisely the territory of the ancient Venetian duchy. The boundaries thus coincided with the old limit of the lagoons (the most extensive of currents), and the mainland reached even the Abbey of St. Hilary and the area of the ancient Altinum.
The Pactum was renewed by kings Charles III (887), Berengar I (888), Guy (891), Rudolf (925), Hugh (927), Otto I (967) and Otto III (983).[6]