He was the oldest son of Count Bernhard of Anhalt by his first wife Brigitte, a daughter of King Canute V of Denmark. Bernhard was enfeoffed with the Duchy of Saxony by Emperor Frederick Barbarossa after the deposition of the Welf duke Henry the Lion in 1180. After his death in 1212, his surviving sons divided his lands according to the laws of the House of Ascania: Henry received the old Ascanian allodial possessions in the Saxon Schwabengau around Ballenstedt, where he established the Principality of Anhalt; while his younger brotherAlbert inherited the Saxon ducal title and retained several unconnected Eastphalian estates around the towns of Wittenberg and Belzig as well as the northern lordship of Lauenburg. Henry initially was a loyal supporter of the Hohenstaufen heir Frederick II, though later he temporarily switched sides to his Welf rival, Emperor Otto IV, was at feud with the Archbishops of Magdeburg, and campaigned the estates of Nienburg Abbey. From about 1215, he began to style himself "Prince", and by Otto's death in 1218 was officially elevated to that rank attending the Hoftag diets of Emperor Frederick II. From 1220 Henry acted as a guardian for the minor sons of his Ascanian cousin, the late Margrave Albert II of Brandenburg, rivalling with both the Magdeburg archbishop Albert I of Käfernburg and his brother, Duke Albert of Saxony. Henry backed Emperor Frederick II during the rebellion of his son Henry in 1234 as well as on his Italian campaigns against the Lombard League, participating in the 1238 Siege of Brescia. Back in Germany, he became involved in the conflict between the Magdeburg archbishop Wilbrand von Käfernburg with his Ascanian cousins, the Margraves of Brandenburg, whereby the Nienburg estates were devastated by the troops of Margrave Otto III in 1242. Both sides reconciled in 1245, mediated by Duke Otto I of Brunswick who married his daughter Matilda, a niece of the Brandenburg margraves, off to Prince Henry's eldest son, Henry II. Henry's most famous ministerialis was Eike von Repgow, a Saxon noble from Reppichau, who compiled the Sachsenspiegel, the most important legal code of the German Middle Ages. The prince also was a renowned Minnesänger. At the beginning of the 14th century, five of his Minnelieder were copied into the Codex Manesse, an exceptionally beautiful collection. In this source, he is erroneously referred to as "Duke". Before his death, about 1245, Henry retired and divided the Anhalt principality between his sons: Henry II inherited Aschersleben, Bernhard received Bernburg, and Siegfried took Zerbst. His youngest surviving sons, Hermann and Magnus, were ordained priests. The House of Ascania ruled the Duchy of Anhalt until 1918.
