The most notable reference to a group of seven Archangels appears to have been borrowed from the Jewish Pseudepigrapha, namely the 250 BC Book of the Watchers, which at some point was merged with some other books in what is known today as 1 Enoch (the Book of Enoch), and was made part of the Ethiopian Christian movement scriptural cannon, though by the seventh century it was rejected by Christian leaders from all other denominations as canonical scripture, and despite having been prevalent in Jewish and early Christian Apostolic traditions (as well as the early Christian leaders writings) the book just fell from academic and religious status in regards to the rest of the canonical scripture, resulting in the text not being found in most parts of the World, as it was forbidden, from 7th Century AD onwards. The list of Angels survived only as part of oral traditions that differed to one another depending on the geographical area that they were present, and thus many different lists of angels (termed "Archangels '') exist, but to different levels of acceptance.
how many arch angels are in the bible
seven seven