[2] The Obotrite realm reached its greatest area during Henry's rule, extending from the Elbe to the Oder and from the Havelland to the Baltic Sea.
Henry remained on good terms with his Danish and Saxon neighbors, especially Duke Lothar von Supplinburg and Adolf I of Holstein.
Helmold records Henry as campaigning against the Rani, Kissini, Circipani, Liutizi, and Western Pomeranians to render them tributary.
In the winters of 1123/24 and 1124/25 Henry led expeditions against the Rani after they killed his son Woldemar and refused to pay tribute.
Henry led 2,000–6,000 men during the first campaign; Saxons from Holstein and Stormarn marched alongside his Slavic troops.
While Henry was besieging Havelberg for a month, his son Mistue plundered the neighboring Linones with 200 Saxons and 300 Slavs.
In retribution, Henry launched large scale raids into Southern Denmark around Schleswig region and proved to be a menace to the Danes, devastating the territory and leaving it "without one farmer".
[3] Saxo also recounts usage of the Wendic battle strategy of tiring out the enemy by circling them on horseback as well as hit and run tactics effective against the armoured opponents, leaving Danish retaliatory attacks unsuccessful because they had not yet mastered transportation of mounted units by ship and had to fight Henry's forces on foot.