Grendel is one of three antagonists, along with Grendel's mother and the dragon, in the Anglo-Saxon epic poem Beowulf (AD 700–1000). Grendel is usually depicted as a monster, though this is the subject of scholarly debate. In the poem, Grendel is feared by all but Beowulf.
The poem Beowulf is contained in the Nowell Codex. As noted in lines 105–114 and lines 1260–1267 of Beowulf, Grendel and his mother are described as descendants of the Biblical Cain. Beowulf leaves Geatland in order to find and destroy Grendel, who has been attacking the mead-hall of Heorot, killing and eating anyone he finds there. Grendel attacks the hall after having been disturbed by the noise of the drunken revellers. One cryptic scene in which Grendel sits in the abandoned hall unable to approach the throne hints that his motives may be greed or revenge. After a long battle, Beowulf mortally wounds Grendel by ripping his arm off. Grendel dies in his cave under the swamp. There, Beowulf later engages in a fierce battle with Grendel's mother, over whom he triumphs. Following her death, Beowulf finds Grendel's corpse and removes his head, which he keeps as a trophy. Beowulf then returns to the surface and to his men at the "ninth hour" (l. 1600, "nōn", about 3 p.m.). He returns to Heorot, where he is given many gifts by an even more grateful Hrothgar.
In 1936, J.R.R. Tolkien's Beowulf: The Monsters and the Critics discussed Grendel and the dragon in Beowulf. This essay was the first work of scholarship in which Anglo-Saxon literature was seriously examined for its literary merits—not just scholarship about the origins of the English language, or what historical information could be gleaned from the text, as was popular in the 19th century.
Debate over description 
During the following decades, the exact description of Grendel became a source of debate for scholars. Indeed, because his exact appearance is never directly described in Old English by the original Beowulf poet, part of the debate revolves around what is known, namely his descent from the biblical Cain (who was the first murderer in the Bible).
Debate over Grendel's nature 
Seamus Heaney, in his translation of Beowulf, writes in lines 1351–1355 that Grendel is vaguely human in shape, though much larger:
- ... the other, warped
- in the shape of a man, moves beyond the pale
- bigger than any man, an unnatural birth
- called Grendel by the country people
- in former days.
Heaney's translation of lines 1637–1639 also notes that his mother's disembodied head is so large that it takes four men to transport it. Furthermore, in lines 983–989, when Grendel's torn arm is inspected, Heaney describes it as being covered in impenetrable scales and horny growths:
- Every nail, claw-scale and spur, every spike
- and welt on the hand of that heathen brute
- was like barbed steel. Everybody said
- there was no honed iron hard enough
- to pierce him through, no time proofed blade
- that could cut his brutal blood caked claw
Peter Dickinson (1979) argued that seeing as the considered distinction between man and beast at the time the poem was written was simply man's bipedalism, the given description of Grendel being man-like does not necessarily imply that Grendel is meant to be humanoid, going as far as stating that Grendel could easily have been a bipedal dragon.
Other scholars such as Kuhn (1979) have questioned a monstrous description, stating:
- There are five disputed instances of āglǣca [three of which are in Beowulf] 649, 1269, 1512...In the first...the referent can be either Beowulf or Grendel. If the poet and his audience felt the word to have two meanings, 'monster,' and 'hero,' the ambiguity would be troublesome; but if by āglǣca they understood a 'fighter,' the ambiguity would be of little consequence, for battle was destined for both Beowulf and Grendel and both were fierce fighters (216–7).
Sonya R Jensen argues for an identification between Grendel and Agnar, son of Ingeld, and suggests that the tale of the first two monsters is actually the tale of Ingeld, as mentioned by Alcuin in the 790s. The tale of Agnar tells how he was cut in half by the warrior Bothvarr Bjarki ('Warlike little Bear'), and how he died 'with his lips separated into a smile'. One major parallel between Agnar and Grendel would thus be that the monster of the poem has a name perhaps composed of a combination of the words gren and daelan. The poet may be stressing to his audience that Grendel 'died laughing', or that he was gren-dael[ed] or 'grin-divid(ed)', after having his arm torn off at the shoulder by 'Beowulf', whose name means 'Bee-Wolf' or 'Bear'.
Grendel in film, literature, and popular culture 
Grendel also appears in Harold E. Varmus' speech that he gave for winning the Nobel Prize in Physiology or Medicine for his work on oncogenes at the Nobel Banquet, December 10, 1989. Harold E. Varmus compared a cancer cell to Grendel as a cancer cell is "like Grendel, a distorted vision of our normal selves".
- Jack, George. Beowulf: A Student Edition. p. 123.
- Williams, David (1982). Cain and Beowulf: A Study in Secular Allegory. Toronto: University of Toronto Press.
- Heaney, Seamus. Beowulf lines 1351–1355.
- Heaney, Seamus. Beowulf lines 983–989.
- Dickinson, Peter. The Flight of Dragons ch.10 "Beowulf". New English Library, 1979.
- Jensen, S R (1998). Beowulf and the Monsters. Sydney: ARRC.
- Hooke, Della. Worcestershire Anglo-Saxon Charter Bounds, 1990, Boydell & Brewer, Worcestershire (England), ISBN 0-85115-276-7.
- Nobel Banquet Speech of Harold E. Varmus
- Jack, George. Beowulf : A Student Edition. Oxford University Press: New York, 1997.
- Jensen, S R. Beowulf and the Monsters. ARRC: Sydney, corrected edition, 1998. Extracts available online.
- ----. Beowulf and the Battle-beasts of Yore. ARRC: Sydney, 2004. Available online.
- Klaeber, Frederick, ed. Beowulf and the Fight at Finnsburg. Third ed. Boston: Heath, 1950.
- Kuhn, Sherman M. "Old English Aglaeca-Middle Irish Olach". Linguistic Method : Essays in Honor of Herbert Penzl. Eds. Irmengard Rauch and Gerald F. Carr. The Hague, New York: Mouton Publishers, 1979. 213–30.
- Tolkien, J.R.R. Beowulf, the Monsters and the Critics. (Sir Israel Gollancz Memorial Lecture, British Academy, 1936). First ed. London: Humphrey Milford, 1937.
- Cawson, Frank. "The Monsters in the Mind: The Face of Evil in Myth, Literature, and Contemporary Life". Sussex, England: Book Guild, 1995: 38-39.
- Gardner, John. "Grendel". New York, 1971.