Ese and Wen
Old Norse sources mention two tribes of gods, the Æsir (or in Old English, the Ése) and the Vanir (which would be in Old English the *Wen, though the word never actually appears in the language). According to the Völuspá, these two tribes went to war when the worlds were still young, because of a visit from a Wan named GullveigR to the Æsir. The precise reasons for her visit or what she exactly did to anger them are unclear. Some have identified her with Fréo (ON Freyja). The Völuspá states that GullveigR practised seiðR (a particular form of magic mentioned in Norse and Iccelandic sources) among the Æsir, while the Ynglinga Saga states that Freyja brought seiðR to them. If Gullveig was Freyja, it could be that she was looking for her wayward husband, ÓðR (commonly assumed to be Wóden), who deserted her. If this is the case, then perhaps she was wreaking havoc among the Æsir through her use of seiðR as an act of revenge on her prodigal husband. Regardless of GullveigR's identity or what she did to anger the Æsir, it is said that they stabbed her with spears and burned her three times. Each time she simply came back to life.
As would be expected, this angered the Vanir and the two tribes of gods went to war. Both sides took heavy losses until finally they called a truce. As part of this truce the two groups of gods exchanged hostages. The Wen gave NjörðR and Freyr to the Æsir, while the Æsir gave Mímir (an old god who guarded the Well of Wisdom and whom some modern scholars believe to be Óðinn's uncle) and Hoenir to the Vanir. The Vanir were very impressed with Hoenir, who was very handsome, and elected him their king. Unfortunately, he turned out to be a very poor king, as he could not make a decision unless Mímir was around. For that reason the Wen chopped off Mímir's head and sent it back to the Æsir. Wóden revived Mímir's head and still consults it for wisdom.
The precise differences between the Æsir and the Vanir have always been a matter of debate. Earlier it was thought that the Ése were primarily war gods and the Wen were primarily fertility gods; however, this overlooks the fact that an Áss (singular of Æsir--in Old English Ós), Þorr, deals heavily with fertility but very little with war, while a Vanr, Fréyja, is associated with war but very little with fertility. A clue to some of the differences between the two may be found in the etymologies of the tribes' names. Old English Ós, Old Norse Áss, and Gothic Ansuz all derive from PIE *ansu,, "spirit, god, demon," which in turn is related to other PIE words meaning "breath, air." The Æsir could then be associated with breath or the dynamistic, animating principle of life. According to the American Heritage Dictionary, Old Norse VanR could derive from the PIE root *wen-, meaning "to strive for, to desire." It gave rise to various words in which an individual must strive to obtain a goal (OE winnan "to strive for, to win") or the emotional state arising from when one has achieved a goal (OE wynn "happiness, joy."). The Wen could then be linked to the emotive and volitive apsects of life--the desire to accompish some goal and the will needed to strive towards it.
Given the sparcity of literary evidence for the gods, we cannot say for certain if the Angles and Saxons observed such distinctions between the gods as dividing them into the pantheons of Æsir and Vanir (or, to put it into Old English, Ése and *Wen). Both the genitive plural Ésa and the singular noun Ós appear in Old English, but we have no way of knowing if these words referred to simply any god (the word Áss was used in such a way in Old Norse, despite their distinctions between two pantheons) or to a member of a specific pantheon of gods. No words such as *Wan (which would be the congnate of Old Norse Vanr) or *Wen (which would be the congnate of Old Norse Vanir) appear in Old English texts, unless *Wan is the prefix of such names as Wanræd. In his book Heathen Gods in Old English Literature, Richard North notes that in a Northumbrian gloss, the Latin word lunaticos is glossed with the Old English word wanseoc. He theories that this could be a compound of a native word for Old Norse Vanr (Wan) and seoc, in other words it would refer to sickness as brought on by the *Wen or Vanir. It would be similar to the word deofulseoc (sickness brought on by the Devil) or, though North doesn't mention it, ælfsogoða (sickness brought on by elves). We know from the Old English charm Wið Færstice that Christian Angles and Saxons believed that both the Ése and elves caused disease. There is no reason that, if they divided the gods into two pantheons like the Old Norse speakers, they wouldn't believe the *Wen caused disease as well. Of course, it is always possible that the wan in wanseoc is related to Old English wana, "want, lack, absence."
In the same book, Richard North also theorises that Bede may have used the Latin word vanitas (meaning "Vainities") in his Historia Ecclesiastica as a reference to a Northumbrian word that sounded similar--namely, an Old English cognate to Old Norse Vanir. He notes that in De Temporum Ratione Bede uses the word vanis (another Latin word dealing with vanity), again perhaps with a Northumbrian homophone in mind. The difficulty with North's theory is that we have no certain means of knowing if Bede meant to make a play on words in using a Latin word that sounds like a possible Old English cognate to Old Norse Vanr. At best, it only opens up the possiblity for us that Bede was.
That having been said, a lack of hard evidence does not automatically mean that the Angles or Saxons did not have such words as *Wan and *Wen as part of their language. There are indications that Old Norse Alfar and Old English Ylfe both may have been synonyms for Vanir. Old Norse Æsir is paired with Álfar in several poetic contects. Such is the case in Skírnismál, Hávamál, Lokasenna, and elsewhere where æsir ok álfar or some variation appears. This pairing is more commen than æsir ok vanir which is primarily seen in Snorri's sources. A parallel is seen in Old English in the charm Wið færstice, where ylfa gescot "shot of elves" is listed beside esa gescot "shot of the Æsir." It is possible that the reason Wen does not appear in Old English is because the preferred term for that race of Gods is Ylfe "Elves." This is strengthened by the fact that Frea (Frey) was given Alfheim as a tooth gift according to the Eddas.
Ultimately, we cannot say that whether or not the Angles, Saxons, and Jutes divided the gods into two pantheons or not. Regardless, given the fact that major gods belong to each of the pantheons in the Old Norse corpus, modern heathen should then seek to worship both tribes with equal enthusiasm and devotion.