After this he served with Tilly against Christian IV of Denmark, and besieged and took Wolfenbüttel. His hopes of obtaining the sovereignty and possessions of the evicted prince of Brunswick-Wolfenbüttel were, after a long intrigue, definitively disappointed. In 1628 he was made a count of the empire. The siege and storm of Magdeburg followed, and Pappenheim, like Tilly, has been accused of the most savage cruelty in this massacre. So much could not be said of his tactics at the battle of Breitenfeld, the loss of which was not a little due to the impetuous cavalry general, who was never so happy as when leading a great charge of horse. The retreat of the imperialists from the lost field he covered, however, with care and skill, and subsequently he won great glory by his operations on the lower Rhine and the Weser in rear of the victorious army of Gustavus Adolphus. Much-needed reinforcements for the king of Sweden were constantly detained by Pappenheim's small and newly raised force in the north-west.