At the height of his reign, Henry ruled over a vast territory stretching from the coast of the North and Baltic seas to the Alps, and from Westphalia to Pomerania.

Henry's mother was Gertrude,[1] only daughter of Emperor Lothair II and Empress Richenza, heiress of the Saxon territories of Northeim and the properties of the Brunones, counts of Brunswick.

King Conrad III had dispossessed Henry the Proud of his duchies in 1138 and 1139, handing Saxony to Albert the Bear and Bavaria to Leopold of Austria.

He divorced her in 1162, apparently under pressure from Emperor Frederick Barbarossa, who did not cherish Guelphish possessions in his home area and offered Henry several fortresses in Saxony in exchange.

[4] By December 1172, he was back in Bavaria[4] and, in 1174, he refused to aid Frederick in a renewed invasion of Lombardy because he was preoccupied with securing his own borders in the east.

When Frederick Barbarossa went on the Crusade of 1189, Henry returned to Saxony, mobilized an army of his faithful, and conquered the rich city of Bardowick as punishment for its disloyalty.

The Henry the Lion Bible is preserved in near-mint condition from the year 1170; it is located in the Herzog August Library in Wolfenbüttel, a town in Lower Saxony.

[16][17][18] The legend of Henry the Lion also inspired the Czech tale of the knight Bruncvík, which is depicted on a column on Charles Bridge in Prague.

The book The Pope's Rhinoceros (1996) by Lawrence Norfolk opens with an allegory of a planned ransack by Henry's army of the monastery at Usedom where purportedly a treasure was kept.

However, the night before the attack the poorly maintained monastery and its treasures crumble into the sea as the result of a storm, and henceforth constituting a loss to the military expedition.