sentences:  Duke Otto the Illustrious (d. 912) served as Hersfeld abbot, his son Henry the Fowler married Hatheburg of Merseburg, a daughter of Count Erwin of Merseburg and heiress of large estates in Hassegau und Friesenfeld.Her brother-in-law, Count Thietmar of Merseburg was one of Henry's tutors.In 909 the couple separated and Hatheburg again took the veil, nevertheless, Henry retained her Eastphalian estates.