Inconsistent Spelling / Myth and Religion

• Nobody seems to know whether "Xenu" or "Xemu" is the correct spelling. At least, nobody who's willing to talk about it.
• The name of Óðinn/Odin/Oden/Woden/Wotan is spelled differently in basically every Germanic language. This is in part due to Norse having a distinct letter ð for the voiced "th" sound, transliterated in modern English sometimes as th and sometimes as d, and in most Scandinavian languages as dh or d. And the Romans called him Mercury.
  • There's also Freyja/Freya/Freia/Freja/Frøya/Freyia. Who is not, however, Frija/Frea/Frigg/Frige/Frigga. (Usually. They are conflated in some versions.)
• The Bible, due to the multiple languages in which the original texts were written or translated. It gets worse with some authors, like Yeshua Ben Sira, whose full name is either Joshua Ben Sira, Jesus, the Son of Sirach, Joshua ben Sira, Jesus ben Sira, etc. The Catholic Church decided to avoid this confusion by naming his book "Ecclesiasticus", but may have made things worse, since it's often confused with Ecclesiastes. Thus, modern translations of Catholic Bibles just call it Sirach.
  • God. He's OK with being called God, since it's clear that He's the only one to which a Christian or Jew would refer, but...YHVH or YHWH? Is the name more closely Anglicized as Yahweh, Jehovah^note Definitely incorrect, as it comes from using the vowels for Adonai (Lord), which is what was supposed to be said instead of the real name, or something in between? It's not supposed to be pronounced. Nobody but the high priest knew how the word was pronounced, and even modern religious Jews misspell it on purpose because they're not allowed to write it. There is some debate about what exactly the word means, but it's likely related to the root 'to exist'.
• Arthurian Legend: The stories were developed over the course of the Middle Ages in Latin, the Brythonic Celtic languages, French, English and even German. Arthur appears in the Latin histories as Arthur, Arthurus and Arturus. Modern writers often interpret his name as a corruption of the Latin family name Artorius and spell it that way. Guinevere can be Guenever, Gwenwhyfar, Guenièvre, Guanhumara, or Wenneuereia. It can also be Jennifer or Ginevra. Similarly for Isolde/Iseult/Isolt/whatever. Really, we could go on like this forever — you can expect any given character to be spelled at least two or three ways.
• Similarly, retellings of the Robin Hood stories often disagree on the spelling of the surname of Robin's Evil Counterpart Guy of Gisbourne/Gisborne/Gisburn etc. Will Scarlet's real family name usually begins with S, but can be Scarlock/Scathelock/Scadlock etc. Then there's another Will whose surname is Stutley/Stukely/Stukeley etc. There's also the Marian/Marion issue. Of course, even among literate people, spelling of names was fairly inconsistent in the Middle Ages as spelling was not yet standardized.
• All over the place in Celtic Mythology. Any given name might show up in multiple possible forms. Queen Méabh from the Táin, for example, might be rendered in Old Irish (Medb), Middle Irish (Meḋḃ), Modern Irish (Méabh) or an English transliteration ranging from the reasonably accurate and modern phonetic (Maeve) to just stripping out the diacritical marks and leaving you to fend for yourself (Meabh).
• The obscure Catholic Saint Winwaloe. Or possibly Guénolé, Winwallus, Guingalois, or Vinguavally. Or maybe Ouignoualey, or Bennoc, or dozens more.
• The Greek names of figures of Classical Mythology may be subject to this, as Greek has a different alphabet from most other European languages such as English^note though paradoxically the Latin Alphabet is an off shoot of one of the earliest Greek Alphabets, yes they had many, but after a few thousand years the phonetic changes made them different enough to cause headaches to translators. . Nearly every character has a Latin transliteration or substitution as well, which may be more common in Western European languages than any attempt to directly transliterate the Greek name.
  • The name of the legendary hero of Greek mythology can be spelled either as Herakles or Heracles. That Other Wiki seems to prefer the latter, as does the Glory of Heracles series. And of course, there's the Roman spelling Hercules, which plenty of other adaptations prefer.
  • The Titan Kronos (known to the Romans as Saturn) often has his name spelled as Cronos or Cronus. It doesn't help that he was often confused (sometimes by the Greeks themselves!) for Chronos/us, the personification of time.
  • The three-headed guard dog of the underworld whom Heracles had to capture as part of his labors can be romanized as either Cerberus or Kerberos, with the latter being used for a computer network authentication protocol.
• There are multiple accepted ways to write "Hanukkah" in Roman letters. One of the more common variants is "Chanukah".
• There are dozens of different ways to spell "wendigo", since the being is found in the mythology of many different Algonquian peoples and thus their languages. About the only consistent traits between the spellings are that most of them start with a W and are three syllables long.
• Similarly, the vampire or, in the earliest English references, vampyre. The same creature (though with wildly divergent interpretations) is found in the folklore of most Slavic peoples, and is variously known as a vampir, upír, upyr, upiór, wąpierz, and so on.
• The holy book of Islam, given that Arabic script doesn't transliterate very precisely to the Roman alphabet, has been identified as the Quran, Qur'an, Koran, Al-Coran, Coran, Kuran, and Al-Qur'an, among others. Likewise, practitioners of the faith have been referred to both as Moslems (especially in the past) and Muslims, and their prophet goes by a number of transliterations including Muhammad, Mohammad, Muhammed, Mohamed, Mohammed, Mohamad, Muhamed, Muhammet, and Muhamet.
• Lusitanian Mythology: As in many Latinized names, there are several variations to the names; Endovelicus was Aendovelicus and, in Portuguese, Endovélico. There is a possible subversion in Bandua's case as the name Bandus might have referred to the god he/she was consort to.