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 brother Albert inherited the Saxon ducal title and retained several unconnected Eastphalian estates around the towns of Wittenberg and Belzig (later Saxe-Wittenberg) 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" (princeps, German: Fürst), and by Otto's death in 1218 was officially elevated to that rank attending the Hoftag diets of Emperor Frederick II.

Henry's most famous ministerialis (bondsman) was Eike von Repgow, a Saxon noble from Reppichau, who compiled the Sachsenspiegel, the most important legal code of the German Middle Ages.

About the year 1211 Henry married Irmgard (c. 1197 – c. 1244), daughter of the Ludovingian landgrave Hermann I of Thuringia and a second cousin of the Hohenstaufen emperor Frederick II through her paternal grandmother Judith of Swabia.