The memebrs of this noble house whose line begins with one SquireBoeselager of Stemmern by Magdeburgon first appearing in the documents on April 12, 1363. The first fully documented member is Henning von Boeselager holding a knight's fief in Wolmirsleben from April 12, 1466. By decree of the Royal Prussian throne, members of the Heesen Line entered the ranks of the barons on December 20, 1823; the members of the Eggermühlen branch were thereafter styled "barons" according to customary law.
Baron Frederick Boeselager-Eggermuhlen, of the 15th Hanoverian Hussars, married at St. Clement's Church, Hanover, Germany, April 11, 1893, Marie Louise Lawlor, daughter of Michael Lawlor, M.D., and his wife, Philomene Caron of Toronto. The couple had two children, Walburga and Ferdinand.