Unlike his literary predecessor, Caedmon, whose biography is solely derived from Bede's Ecclesiastical History, Cynewulf's life is a veritable mystery to scholars. Furthermore, the “facts” that have been gleaned from the literature of Cynewulf “somewhat reverse” what we know of Caedmon's own writings. The four signed poems of Cynewulf are vast in that they collectively comprise several thousand lines of verse. In comparison, Caedmon's only known work, his Hymn, is quite succinct at nine-lines. Thus, while scholars have little insight into Cynewulf’s life, they can analyze the poet’s verse to its deepest roots, uncovering a stock of evidence that can shed light onto the poet’s being. Despite new discoveries, Cynewulf remains “the shadow of a name.”
The origin and date of Cynewulf are topics of debate for contemporary historians; but some basic statements can be made by examining such aspects as the dialect of the poet, and variations in the spelling of his name. Though the Vercelli and Exeter manuscripts were primarily late West-Saxon in their scribal translations, it is most probable that Cynewulf wrote in the Anglian dialect and it follows that he resided either in the province of Northumbria or Mercia.
This is shown through linguistic and metrical analysis of his poems, ie. “Elene,” where in the poem’s epilogue (beginning l.1236) the “imperfect rhymes” become corrected when Anglian forms of the words are substituted for the West-Saxon forms., For instance, the manuscript presents the miht:peaht false rhyme which can be corrected when the middle vowel sounds of both words are replaced with an æ sound. The new maeht:paeht rhyme shows a typical Anglian smoothing of the ea. Numerous other “Anglianisms” in Elene and Juliana are indicative of an original Anglian dialect underlying the West-Saxon translation of the texts. Any definite conclusion to Cynewulf being either Northumbrian or Mercian has been hard to come by, but linguistic evidence suggests that the medial e in the signed Cynewulf would have, during the broad window period of Cynewulf’s existence, been characteristic of a Mercian dialect.
The date of Cynewulf is an even more debatable subject for scholars. Any attempt to link the man with a documented historical figure has met failure or resulted in an improbable connection. What can be deduced is that Cynewulf’s date is no earlier than the dates of the Vercelli and Exeter manuscripts, which are approximately in the second half of the tenth century. However, the presence of early West Saxon forms in both manuscripts means that it is possible an Alfredian scribe initially translated Cynewulf’s verse, placing him no earlier than the turn of the tenth century. 
Even more puzzling, the two textual variations of Cynewulf’s name, Cynewulf and Cynwulf, come after a time when the older spelling of the name was Cyniwulf. A Dr. Sisam points out that the i tends to change to an e about the middle of the eight century, and the general use of the i phases itself out by the end of the century, suggesting Cynewulf cannot be dated much before the year 800. Moreover, it has been argued that the “cult of the cross,” which can finds ground in Cynewulf’s Elene, achieved its cultural apex in the eighth century. This last assumption has been discounted due to evidence that hints that the intense worship of the cross was much more prolonged. Also deserving consideration is the argument that the acrostic was most fashionable in ninth century poetry and Cynewulf’s own acrostic signature would have been following the trend during this time.. All the evidence considered, no exact deduction of Cynewulf’s date is accepted, but it is likely he flourished in the ninth century.
It was at one time believed that Cynewulf could be one of three documented figures: Cynewulf, Bishop of Lindisfarne (d. about 782), Cynwulf, a Dunwich priest (fl.803), and Cenwulf, Abbot of Peterborough (d.1006). The most plausible conjecture is that he was Cynewulf of Lindisfarne; the rationale for this argument being that Cynewulf’s elaborate religious pieces must lend themselves to “the scholarship and faith of the professional ecclesiastic speaking with authority. Yet at least a few contend that the environment of the time was not conducive to poetic invention.
Nevertheless, several things can be surmised by examining his works. Cynewulf was without question a literate and educated man, since there is no other way we can "account for the ripeness which he displays in his poetry."  Given the subject matter of his poetry he was likely a "man in holy orders," and the deep Christian knowledge conveyed through his verse implies that he was well learned in ecclesiastical and hagiographical literature, as well as the dogma and doctrine of the Roman Catholic Church.  His apparent reliance on Latin sources for inspiration also means he knew the Latin language, and this of course would correlate with him being a man of the Church.
Early scholars for a long while assigned a plethora of Old English pieces to Cynewulf on the basis that these pieces somewhat resembled the style of his signed poems.  It was at one time plausible to believe that Cynewulf was author of the Riddles of the Exeter Book, the Phoenix, the Andreas, and the Guthlac; even famous unassigned poems such as the Dream of the Rood, the Harrowing of Hell, and the Physiologus have at one time been ascribed to the man. However, the studies of S.K. Das and Claes Schaar prompted academia to limit Cynewulf’s canon to the four poems which bear his acrostic mark. The Exeter Book, which is extraordinary in its scope of subject matter, holds Cynewulf’s Juliana and Christ II (The Ascension). In the Vercelli Book, on the other hand, his Elene and Fates of the Apostles are found.
All four of Cynewulf's poems contain passages where the letters of the poet’s name are woven into the text using runic symbols that also double as meaningful ideas pertinent to the text. In Juliana and Elene, the interwoven name is spelled in the more recognizable form as Cynewulf, while in Fates and Christ II it is observed without the medial e so the runic acrostic says Cynwulf. All four poems draw upon Latin sources such as homilies and hagiographies (the lives of saints) for their content, and this is to be particularly contrasted to other Old English poems, e.g. Genisis, Exodus, and Daniel, which are drawn directly from the Bible as opposed to secondary accounts. The poems, like a substantial portion of Anglo-Saxon poetry, are sculpted in alliterative verse.
In terms of length, Elene is by far the longest poem of Cynewulf’s corpus at 1,321 lines. It is followed by Juliana, at 731 lines, Christ II, at 427 lines, and The Fates of the Apostles, at a brisk 122 lines. Three of the poems are “martyrolical,” in that the central character(s) in each die/suffer for their religious values. In Elene, Saint Helena endures her quest to find the Holy Cross and spread Christianity; in Juliana, the title character dies after she refuses to marry a pagan man, thus retaining her Christian integrity; in Fates of the Apostles, the speaker creates a song that meditates on the deaths of the apostles which they “joyously faced.” Elene and Juliana fit in the category of poems that depict the lives of saints. These two poems along with Andreas and Guthlac (parts A and B) constitute the only versified saints’ legends in the Old English vernacular. The Ascension is outside the umbrella of the other three works, and is a vehement description of a “devotional subject.”
The exact chronology of the poems is not known. One argument asserts that Elene is likely the last of the poems because the “autobiographical” epilogue implies that Cynewulf is old at the time of composition, but this view has been doubted. Nevertheless, it seems that Christ II and Elene represent the cusp of Cynewulf’s career, while Juliana and Fates of the Apostles seem to be created by a less inspired, and perhaps less mature, poet.
It is common knowledge that the runes comprised an ancient alphabet of the Germanic people, and they were used by Anglo-Saxons before the advent of the Roman alphabet. Yet what is not so certain is the meaning of each rune in the context of Cynewulf’s poesy. It is understood that the each rune represented a letter, and we do have standard meanings for each of the runes Cynewulf uses:
The importance of Cynewulf’s signatures can be seen in two lights.
On one hand, Cynewulf’s use of runic inscriptions is of astounding importance to students of the history of literature. The practice of claiming authorship over one’s poems was a break from the tradition of the anonymous poet, where no composition was viewed as being owned by its creator. It had been customary of classical poets to hand down their versified works with the expectation the work would be modified and changed so as to lose its original structure. Cynewulf devised a tradition where authorship would connote ownership of the piece and an originality that would be respected by future generations. Furthermore, by integrating his name, Cynewulf was attempting to retain the structure and form of his poetry that would “undergo mutations” otherwise.
From a different perspective, Cynewulf’s intent was not to claim authorship, but to "seek the prayers of others for the safety of his soul." It is contended that Cynewulf wished to be remembered in the prayers of his audience in return for the pleasure they would derive from his poems. In a sense his expectation of a spiritual reward can be contrasted with the material reward that other poets of his time would have expected for their craft.
Cynewulf’s justification as a poet stems from the idea that "poetry" was "associated with wisdom."  In his Christ II, Cynewulf writes the following:
Then he who created this world…honoured us and gave us gifts…and also sowed and set in the mind of men many kinds of wisdom of heart. One he allows to remember wise poems, sends him a noble understanding, through the spirit of his mouth. The man whose mind has been given the art of wisdom can say and sing all kinds of things.
By looking at Cynewulf’s autobiographical reflection in the epilogue of Elene, it is evident that he believes his own skill in poetry comes directly from God, who "unlocked the art of poesy" within him. 
His poem "Christ II" contains a reference to a "Middle-earth" and affected the development of J.R.R. Tolkien's legendarium, specifically the Eärendil legend.