He died on October 15, 898 in Marengo, Italy. Reigned for six years as Holy Roman emperor at the end of the Carolingian period.
Crowned co-emperor with his father, Guy of Spoleto, at a ceremony in Ravenna in 892, Lambert ruled alone after his father’s death in 894. The following year Arnulf of Carinthia, king of Germany, invaded Italy and besieged Rome, taking the city in February 896. He was crowned emperor by Pope Formosus, who declared Lambert deposed. Marching on Spoleto, Arnulf was suddenly taken ill and had to return to Germany, leaving Lambert once more in possession of the empire.
A year after Formosus’ death in 896. Lambert avenged the Pope’s crowning of Arnulf by having Formosus body exhumed by the new pope, Stephen VI (VII), dressed in his pontifical robes, and tried and convicted in St. Peter’s for a variety of crimes. The naked and mutilated body was then flung into a potter’s field and eventually thrown into the Tiber. Stephen was assassinated in 897.
In 898 Berengar, marquis of Fruili, Guy of Spoleto’s former rival, marched on Pavia. Lambert, who had been hunting near Marengo, south of Milan, counterattacked, defeating Berengar. Returning to Marengo, he was killed, either by assassination or by a fall from his horse.