Adelchis was the son of Radelchis I

Radelchis I of Benevento

Radelchis I was the treasurer, then prince of Benevento from 839, when he assumed the throne upon the assassination of Sicard and imprisonment of Sicard's brother, Siconulf, to his death, though in his time the principality was divided.According to the Chronica S...

, Prince of Benevento, and successor of his brother Radelgar

Radelgar of Benevento

Radelgar was the eldest son of Radelchis I of Benevento and he succeeded him as Prince of Benevento on his death in 851. Radelgar's mother was Caretrude and his brother was Adelchis....

 in 854.

It was given to Adelchis to preserve the ancient principality and its independence in the face of repeated assaults by the Saracens from the south, the Emperor Louis II from the north, and Byzantine

Byzantine Empire

The Byzantine Empire was the Eastern Roman Empire during the periods of Late Antiquity and the Middle Ages, centred on the capital of Constantinople. Known simply as the Roman Empire or Romania to its inhabitants and neighbours, the Empire was the direct continuation of the Ancient Roman State...

 Langobardia to the east. At first, he was unsuccessful in his wars with the Moslems. He was defeated at Bari

Bari

Bari is the capital city of the province of Bari and of the Apulia region, on the Adriatic Sea, in Italy. It is the second most important economic centre of mainland Southern Italy after Naples, and is well known as a port and university city, as well as the city of Saint Nicholas...

 in 860 and forced to make a truce with the emir and pay a tribute. In subsequent ventures, he was forced to call in the help of the emperor. In 866, the emperor defeated the Saracens and, in 871, Bari itself fell. Louis then tried to set up greater control over all the south by garrisoning his troops in Beneventan fortresses.

The response of Adelchis to this action was to imprison and rob the emperor while he was staying the princely palace at Benevento in August. A month later, the Saracens had landed with a new invasive force and Adelchis released Louis to lead the armies against it. Adelchis forced Louis to vow never to reenter Benevento with an army or to take revenge for his detention. Louis went to Rome

Rome

Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...

 in 872 and was released from his oath by Pope Adrian II

Pope Adrian II

Pope Adrian II , , pope from December 14, 867 to December 14, 872, was a member of a noble Roman family, and became pope in 867, at an advanced age....

 on 28 May. He tried to exact punishment on Adelchis, but was not very successful. Adelchis turned to the Byzantines. He was assassinated in May 878.

He was notably the last Lombard ruler to revise the Edictum Rothari

Edictum Rothari

The Edictum Rothari was the first written compilation of Lombard law, codified and promulgated 22 November 643 by King Rothari. The custom of the Lombards, according to Paul the Deacon, the Lombard historian, had been held in memory before this...

.

Adelchis' daughter was Ageltrude

Ageltrude

Ageltrude was the Holy Roman Empress and Queen of Italy as wife and mother respectively of Guy and Lambert...

, wife of Guy III of Spoleto

Guy III of Spoleto

Guy of Spoleto , sometimes known by the Italian version of his name, Guido, or by the German version, Wido, was the Margrave of Camerino from 880 and then Duke of Spoleto and Camerino from 883. He was crowned King of Italy in 889 and Holy Roman Emperor in 891...

.

Sources

• Elke Goez. Geschichte Italiens im Mittelalter. Darmstadt: WBG, 2010, pp. 60–61.