In 1139, Henry was betrothed to Sophia, daughter of King Béla II of Hungary.
After several letters to her brother, King Géza II, she received permission to remain in the German monastery where she had been living.
[7][8] During his father's absence on crusade (June 1147–May 1149), he was placed under the tutorship of the powerful abbot Wibald and the notary Heinrich von Wiesenbach [de].
[7] Nine letters (eight in full) written by or for Henry survive from this period of his reign,[7] but no diplomas do.
[10] The military prowess of the young ruler was emphasised in letters (dated the week of 16–20 April 1150 at Würzburg) to the Byzantine emperor, Manuel I, and the empress, Irene, Gertrude's sister, informing them of the victory.