The duke remained a loyal follower of the Hohenstaufens and in May 1147 accompanied King Conrad on the Second Crusade. When they suffered a disastrous defeat at the Battle of Dorylaeum against the Seljuk Turks in October, Henry narrowly escaped together with Conrad's nephew, young Frederick Barbarossa. Later on, he attended the Council of Acre along with king Conrad III and Frederick Barbarossa, then the Siege of Damascus. On their way home, Henry stayed at the court of the Byzantine emperor Manuel I Komnenos, where he married his niece Theodora in late 1148.