Berengar I (Latin: Berengarius, Perngarius; Italian: Berengario; c. 845 – 7 April 924) was King of Italy from 887 and Holy Roman Emperor from 915 until his death in 924. He is usually known as Berengar of Friuli, since he ruled the March of Friuli from 874 until at least 890, but he had lost control of the region by 896.
Berengar rose to become one of the most influential laymen in the empire of Charles the Fat, and he was elected to replace Charles in Italy after his deposition in November 887. His long reign of 36 years saw him opposed by no fewer than seven other claimants to the Italian throne, and it is usually characterised as troubled because of the many competitors for the crown and the arrival of Magyar raiders in Western Europe. His death was followed by an imperial interregnum that lasted 38 years until the German King, Otto I, was crowned emperor in 962.
Berengar's family was called the Unruochings after his grandfather, Unruoch II of Friuli. Berengar was a son of Eberhard of Friuli and Gisela, a daughter of Louis the Pious and his second wife Judith. He was thus of Carolingian extraction on his mother's side. He was born probably at Cividale. Sometime during his margraviate, he married Bertila, daughter of Suppo II, thus securing an alliance with the powerful Supponid family. She would later rule alongside him as a consors, a title specifically denoting her informal power and influence, as opposed to a mere coniunx, "wife".
When his older brother Unruoch III died in 874, Berengar succeeded him in the March of Friuli. With this he obtained a key position in the Carolingian Empire, as the march bordered the Croats and other Slavs who were a constant threat to the Italian peninsula. He was a territorial magnate with lordship over several counties in northeastern Italy. He was an important channel for the men of Friuli to get access to the emperor and for the emperor to exercise authority in Friuli. He even had a large degree of influence on the church of Friuli. In 884–885, Berengar intervened with the emperor on behalf of Haimo, Bishop of Belluno.
When, in 875, the Emperor Louis II, who was also King of Italy, died, after having come to terms with his uncle Ludwig the German whereby Ludwig's eldest son, Carloman, would succeed in Italy, Charles the Bald of West Francia invaded the peninsula and had himself crowned king and emperor. Ludwig the German sent first Charles the Fat, his youngest son, and then Carloman himself, with armies containing Italian magnates led by Berengar, to possess the Italian kingdom. This was not successful until the death of Charles the Bald in 877. The proximity of Berengar's march to Bavaria, which Carloman already ruled under his father, may explain their cooperation.
In 883, the newly succeeded Guy III of Spoleto was accused of treason at an imperial synod held at Nonantula late in May. He returned to the Duchy of Spoleto and made an alliance with the Saracens. The emperor, then Charles the Fat, sent Berengar with an army to deprive him of Spoleto. Berengar was successful before an epidemic ravaged all Italy, affecting the emperor and his entourage as well as Berengar's army, and forced him to retire.
In 886, Liutward, Bishop of Vercelli, took Berengar's sister from the nunnery of San Salvatore at Brescia in order to marry her to a relative of his; whether or not by force or by the consent of the convent and Charles the Fat, her relative, is uncertain. Berengar and Liutward had a feud that year, which involved his attack on Vercelli and plundering of the bishop's goods. Berengar's actions are explicable if his sister was abducted by the bishop, but if the bishop's actions were justified, then Berengar appears to have initiated the feud. Whatever the case, bishop and margrave were reconciled shortly before Liutward was dismissed from court in 887.
By his brief war with Liutward, Berengar had lost the favour of his cousin, the emperor. Berengar came to the emperor's assembly at Waiblingen in early May 887. He made peace with the emperor and compensated for the actions of the previous year by dispensing great gifts. In June or July, Berengar was again at the emperor's side at Kirchen, when Louis of Provence was adopted as the emperor's son. It is sometimes alleged that Berengar was pining to be declared Charles' heir and that he may in fact have been so named in Italy, where he was acclaimed (or made himself) king immediately after Charles' deposition by the nobles of East Francia in November that year (887). On the other hand, his presence may merely have been necessary to confirm Charles' illegitimate son Bernard as his heir (Waiblingen), a plan which failed when the pope refused to attend, and then to confirm Louis instead (Kirchen).
Berengar was the only one of the reguli (petty kings) to crop up in the aftermath of Charles' deposition besides Arnulf of Carinthia, his deposer, who was made king before the emperor's death. Charter evidence begins Berengar's reign at Pavia, in the Basilica of San Michele Maggiore, between 26 December 887 and 2 January 888, though this has been disputed. Berengar was not the undisputed leading magnate in Italy at the time, but he may have made an agreement with his former rival, Guy of Spoleto, whereby Guy would have West Francia and he Italy on the emperor's death. Both Guy and Berengar were related to the Carolingians in the female line. They represented different factions in Italian politics: Berengar the pro-German and Guy the pro-French.
In Summer 888, Guy, who had failed in his bid to take the West Frankish throne, returned to Italy to gather an army of Spoletans and Lombards to oppose Berengar. This he did, but the battle they fought near Brescia in Autumn was a slight victory for Berengar, though his forces were so diminished that he sued for peace nevertheless. The truce was to last until 6 January 889.
After the truce with Guy was signed, Arnulf of Germany endeavoured to invade Italy through Friuli. Berengar, in order to prevent a war, sent dignitaries (leading men) ahead to meet Arnulf. He himself then had a meeting, sometime between early November and Christmas, at Trent. He was allowed to keep Italy, as Arnulf's vassal, but the curtes of Navus and Sagus were taken from him. Arnulf allowed his army to return to Germany, but he himself celebrated Christmas in Friuli, at Karnberg.
Early in 889, their truce having expired, Guy defeated Berengar at the Battle of the Trebbia and made himself sole king in Italy, though Berengar maintained his authority in Friuli. Represented by his counsellor Walfred at the city of Verona, he remained master in Friuli, which was always the base of his support. Though Guy had been supported by Pope Stephen V since before the death of Charles the Fat, he was now abandoned by the pope, who turned to Arnulf. Arnulf, for his part, remained a staunch partisan of Berengar and it has even been suggested that he was creating a Carolingian alliance between himself and Louis of Provence, Charles III of France, and Berengar against Guy and Rudolph I of Upper Burgundy.
In 893, Arnulf sent his illegitimate son Zwentibold into Italy. He met up with Berengar and together they cornered Guy at Pavia, but did not press their advantage (it is believed that Guy bribed them off). In 894, Arnulf and Berengar defeated Guy at Bergamo and took control of Pavia and Milan. Berengar was with Arnulf's army that invaded Italy in 896. However, he left the army while it was sojourning in the March of Tuscany and returned to Lombardy. A rumour spread that Berengar had turned against the king and had brought Adalbert II of Tuscany with him. The truth or falsehood of the rumour cannot be ascertained, but Berengar was removed from Friuli and replaced with Waltfred, a former supporter and highest counsellor of Berengar's, who soon died. The falling out between Berengar and Arnulf, who was crowned Emperor in Rome by Pope Formosus, has been likened to that between Berengar II and Otto I more than half a century later.