Patmos was actually Pithom in Egypt

 The Isle we currently identify with Patmos was mentioned rarely in Antiquity, and it's known that it was originally named Letois after Leto because of myths about Artemis raising it out of the Sea at the request of Selene.  It's not till the Fourth Century any Church commemorating John writing Revelation was founded there.  There are lists from sources like Tacitus of islands being used as penal colonies by Rome in the 1st Century and Patmos/Letois is never among them.

I've expressed on my other blog that The Beloved Disciple was Mary Magdalene not any of the 12, and that she wrote the Gospel and Epistles commonly attributed to John, or at least 1 John. I think Letois was identified with Patmos derivative of the erroneous John in Ephesus tradition.

The New Testament talks about Ephesus more then any other location that's not in Israel, never is anyone named John ever there.  Remember Ephesus is also where Timothy was when Paul wrote two Pastoral Epistles to him.  Revelation includes a message for Ephesus and other Churches in Asia which people often think implies John knew them.  But I feel it would have proven the Supernatural quality of this message better if it was able to address their issues so well even though this John had never been anywhere near them.

The John of Revelation however does not actually claim to be one of the 12 or a Son of Zebedee.

Revelation 1:9 is the only verse in all of Scripture the name "Patmos" appears in, the spelling is actually for grammatical reasons PatmO in the Textus Receptus.  It's called an Isle, and John says he's there for the Testimony of Jesus and alludes to tribulation, but there is still no direct reference to it being an exile as tradition has assumed it to be.  

There are times in Scripture where the name of a City on an Island is treated as the name of that Island, like Melita/Melite in Acts 28:1.

Last time I flirted with this idea of an alternate location for Patmos I wound up going down the Cyprus/Paphos route for a somewhat arbitrary reason, but now I have a better theory.

Around February 23rd 2023 I visited Pithom's Wikipedia page and the Greek transliteration of the name listed was Πατούμος Patoúmos, a spelling that is literally Patmos with an ού added in the middle.  This spelling apparently comes from Herodotus Histories II.158 where my version (Translated by G.C.Macaulay and Revised by Donald Lateiner, published by Barnes & Noble Classics) transliterates it Patumos.

Now at face value calling Pithom a island may seem weird, but it's in the Nile Delta, I don't think we can rule out the possibility that someone in Pithom in the first or early second century would have thought of it as being an island.  A lot of these kinds of terms were not defined as strictly as how we define them today, the Peloponnese was sometimes called an island for example. There is also debate about the location of Pithom, the reference in Herodotus with this spelling places it by the Royal Canal. 

Pithom is a Biblical location from Exodus 1:11, a lot in Revelation is thematically presenting itself as a repeat of the history of The Exodus.  And there apparently are some Hebrew texts where there is no letter for O between the letters for Th and M which could explain this Patmos spelling's one difference from Herodotus.

The oldest surviving texts we have of Revelation are from Egypt, some examples being Papyrus 47, 98 and 115, but that's true of a lot of Ancient Texts, the Nile Valley is for Climate reasons a place where more ancient texts survived then in other regions.

I now suspect John of Revelation was John Mark, tradition does say he was in Egypt.  The function Mark is serving in Acts 13-14 is essentially the same one John is performing in Revelation.  2 Timothy 4:11 does also tell us Mark had been with Timothy at Ephesus for a time.