Modthryth is a reconstructed name for a character who figures as the queen of King Offa in which Old English epic poem?
Modthryth Modthryth, Thryth ('strength', cf. Old Norse Þrúðr, the daughter of Thor), and Fremu are reconstructed names for a character who figures as the queen of King Offa in "Beowulf".
Barrow-wight Barrow-wights are wraith-like creatures in J. R. R. Tolkien's world of Middle-earth, based on Old Norse beliefs such as Draugr or vǣttr (wights). "Barrow" refers to the burial mounds they inhabited and "wight" is a Middle English word for "living being" or "creature", especially "human being". It does not necessarily mean "spirit" or "ghost"; it is cognate to modern German "Wicht", meaning small mythical creatures (also "Wichtelmännchen"). Tolkien borrowed this concept from Norse mythology, see e.g. "Waking of Angantyr" and "Hrómundar saga Gripssonar". The name "Barrow-wight" itself was first recorded in 1869 in the Eiríkr Magnússon and William Morris translation of "Grettis saga", which features a fight with such a creature. In Norway, farmers of the 19th century were still concerned about "vetter" (wights) around old viking barrows, when these were first excavated.