Yahshuah
The pentagrammaton or Yahshuah is an allegorical form of the Hebrew name of Jesus, constructed from the Biblical Hebrew form of the name, Yeshua, but altered so as to contain the letters of the Tetragrammaton. Originally found in the works of Henry Cornelius Agrippa, Athanasius Kircher, Johann Baptist Grossschedel and other late Renaissance esoteric sources.
The essential idea of the pentagrammaton is of an alphabetic consonantal framework Y-H-Sh-W-H, which can be supplied with vowels in various ways.
Renaissance occultism
The first ones to use the name of Jesus something like "Yahshuah" were Renaissance occultists. In the second half of the 16th century, when knowledge of Biblical Hebrew first began to spread among a significant number of Christians, certain esoterically minded or occultistic circles came up with the idea of deriving the Hebrew name of Jesus by adding the Hebrew letter shin ש into the middle of the Tetragrammaton divine name yod-he-waw-he יהוה to produce the form yod-he-shin-waw-he יהשוה.This was given a basic Latin transliteration JHSVH or IHSVH or IHSUH. This could then be supplied with further vowels for pronounceability. By coincidence, the first three letters of this consonantal transcription IHSVH, etc. were identical with the old IHS/JHS monogram of the name of Jesus.
In Renaissance occultist works, this pentagrammaton was frequently arranged around a mystic pentagram, where each of the five Hebrew letters י ה ש ו ה was placed at one of the points. One of the earliest attested examples of this diagram is in the Calendarium Naturale Magicum Perpetuum or "Magical Calendar" of either Theodor de Bry or Matthäus Merian the Elder. The idea of the pentagrammaton was funneled into modern occultism by 19th-century French writer Eliphas Levi and the influential late 19th-century Hermetic Order of the Golden Dawn. The Golden Dawn favored the consonantal transcription IHShVH or YHShVH, and the pronunciation Yeheshuah.
In Hebrew and Aramaic, the name "Jesus"/"Yeshua" appears as yod-shin-waw-`ayin יֵשׁוּעַ Yeshua and as the longer form of the same name, yod-he-waw-shin-`ayin יְהוֹשֻׁעַ "Joshua"/"Yehoshua". The letter `ayin ע was pronounced as a voiced pharyngeal consonant sound in ancient Hebrew and some Aramaic languages, as opposed to the pronounced sound or a silent Hebrew letter he ה. It however commonly was not pronounced, especially at the end of words in various Palestinian Aramaic dialects.