An Etymological Dictionary of the German Language/Annotated/semperfrei
semperfrei, adjective, ‘free-born, entitled to act as assessor of the synod,’ from Middle High German sëmpervrÎ, ‘subject only to the emperor and empire, authorised to hold a synod or to take part in it.’ Allied to Middle High German sënt, masculine, ‘senatus, diet, imperial diet,’ also ‘ecclesiastical assembly,’ like Old High German sënot (Latin synodus); Middle High German sëmpœre, sëntbœre, properly, ‘authorised to take part in a synod.’