Reign of Charles the Fat
Louis the Younger died in January 882 and was succeeded by Charles the Fat, who was made Emperor of the Carolingian realm the year before and reunited the East Frankish kingdom of his father Louis the German. Under Charles, Henry's career was a succession of battles with Viking raiders. Charles almost immediately sent Henry with an army to besiege Asselt, where an army of Vikings was encamped. According to the Annals of Fulda, Henry and Charles's nephew Arnulf led the advance guard, with Henry in charge of the Frankish contingent and Arnulf leading the Bavarian troops. Charles arrived with the main force in May 882.
Having received oaths from the Viking leaders, the siege of Asselt was considered a success and the Frankish army withdrew. After spending some time at his Christmas court in 882, the emperor sent Henry against some Vikings who had raided Deventer. According to the Annals of Fulda, Henry "settled matters as well as he could, and returned." In late 883, Henry marched against the Vikings again, inflicting severe losses on them. According to the Annals of Fulda, "it is said that not one escaped". Henry, however, was wounded in the fighting.
In 884, Henry won two more victories over the Vikings, slaughtering them "wherever they wanted to go to plunder", according to the annalist of Fulda. Some Vikings who had been harrying West Francia then overwintered in the Hesbaye in 884–85. In early 885, Henry and Archbishop Liutbert of Mainz surprised them in their camp. The survivors fled by night, leaving their plunder behind. Henry and Liutbert are the most prominent men (after the Carolingian kings) in the latter part of the Mainz recension of the Annals of Fulda. This is probably because its author was a partisan of Louis the Younger, as Henry and Liutbert had been Louis's chief advisors.
In 885, Godfrid, one of the Viking leaders at Asselt who had sworn oaths to Charles, taken baptism and received Frisia, was accused of plotting with the emperor’s cousin Hugh to seize Lotharingia. Henry tricked him into a meeting and killed him with his followers. According to the Annals of Saint-Vaast, one of Godfrid's followers, Gerolf, defected and plotted Godfrid's downfall with Henry. Henry then captured Hugh at Gondreville and handed him over to the emperor, who had him blinded and imprisoned in the monastery of Saint Gall.
In 885, a large Viking force laid siege to Paris. The defence of the city fell to Bishop Joscelin and Count Odo. According to the Annals of Saint-Vaast, after the Vikings destroyed one of Paris's towers, Joscelin sent Count Erkenger of Melun to East Francia with specific instructions to ask Henry to come with an army.
As a result, in 886 Henry led the first army to relieve the siege. it was in the field from 9 February until 1 May, but its only actions were skirmishes with Vikings who occasionally strayed too far from their fortifications. By July, Charles himself was leading a huge army towards Paris. Henry was again sent off with an advance guard while the emperor was still at Metz. It was during this expedition that Henry's horse fell into a trap near Quierzy and he was cut off from his men and killed on 28 August. The same basic account of Henry's death is found in the Annals of Saint-Vaast, the chronicle of Regino of Prüm and the Annals of Fulda.
