The origins of the Hermetic Order of the Golden Dawn, the wellspring of  almost all modern occult thought and practice, is a matter of some controversy. The Golden Dawn was founded on the discovery of a manuscript  in cipher that, when subsequently deciphered, formed the basis of its ritual. Where this ritual ultimately originated is a mystery as is the  role of an address that was found with the manuscript, an address of a  Rosicrucian adept in Germany who was to give permission for the "re-establishment" of an English branch of the Order.

Can the origin of the Golden Dawn to be found in a Masonic lodge? I believe so. The clues for the Masonic genesis of Golden Dawn are many. The name of the Order as given in the Cypher Ms is in Hebrew, ChBRTh ZRCh AVR BQD, or according to westcott's translation, Chabrath Zerek Aour Bokhr or "Society of the Shining Light of Dawn". Gerald Suster, in a short essay rebuffing some of the claims of Ellic Howe, who wrote the definitive  history of the Golden Dawn, quotes from Gershom Scholem's book From Berlin to Jerusalem to the effect that there was a "so-called Frankfurt Jewish Masonic Lodge named Chabrath Zereh Boqer Aour". This I believe is no coincidence.

The Frankfurt Jewish lodge did exist. It was chartered on June 17 1807
as Loge St. John de L'aurore Naissante by the Grand Orient of France when Frankfurt was occupied by the Grande Armee of Napoleon. A number of Jews petitioned the Grand Orient for a charter since they could not gain entry into the anti-Semitic German lodges of the day.  L'aurore Naissante admitted both Jews and Gentiles, raising the Jewish members up to the degree of Master Mason, but the Christian members were entitled to the option of progressing through the "higher degrees" of the Scot Rite degrees which barred Jewish members from participation due to their Christian nature.

As part of the French Empire all restrictions against Jews had been lifted but with Napoleon's defeat toleration ended and the Jewish Freemasons were again ostracised. With the withdrawal of Napoleon's troops it was thought expedient not to be associated with anything French, so L'aurore Naissante immediately deleted any reference to the Grand Orient in its materials, changed its name to Loge zur aufgehenden Morgenrothe, and began to look for another obedience to associate with.

They applied to Prince Carl von Hessen, himself a mason and one of the "movers and shakers" of the "Asiatic Brethren" which not only admitted both Jews and Gentiles but was also very involved in mystical, even occult, elements of Freemasonry and kaballah. Negotiations eventually broke down. Eventually in 1817 Morgenrothe found the full recognition it was seeking through August  Frederick, Duke of Sussex, the Grand Master of the United Grand Lodge of England, who empowered the lodge to operate as a Masonic lodge without any restrictions, with the added assurance that "parallel degrees would be instituted for them". Morgenrothe eventually left UGLE for membership in the Eclectic Covenant of Frankfurt in 1870.

One of the great points of significance in the history of the Morgenrothe  is the desire for an alternative to the Scottish Rite accessible to Jewish  members. It is possible that the Chabrath Zereh Boqer Aour was created to replace the Scot Rite and from this desire a set of rituals were drafted and discussed but never used. This possibility is made more intriguing by  the fact westcott gave the name of the German "Mother Temple" of the Golden Dawn as Lichte, Liebe, Leben or in English "Light, Love, Life";,. which is also the motto of the 18º of the Scot Rite of Freemasonry.

It is also perhaps significant that in English Masonry the Scot Rite is know as the Rose Croix, or Rose Cross, degrees. It is also worth noting that many of the foundation members were associated with both Baron von Hund's Strict Observance Freemasonry as well as the Asiatic Brethren, both systems were full of mystical speculation.  If this is the case how did the Cypher ms fall into the hands of Mathers and westcott? 

Rafal Prinke in his essay "The Deeper Roots of the Golden Dawn" provides the information that in 1817 the Duke of Sussex also chartered a daughter lodge of the Morgenrothe in London called "Aurore naissante";, which was closed down in 1822 at the request of its motherlodge. Prinke suggests that the lodge ceased Masonic operation but survived as a form of esoteric study group. Prinke also suggests that Lord Bulwer-Lytton, a noted Rosicrucian, first made contact with the London group and from there received an introduction to a "Rosicrucian lodge in Frankfurt".. meaning the esoteric element in the Jewish Morgenrothe lodge. From there he received a copy of the cipher manuscript which was acquired by his friend Frederick Hockley after his death. 

Hockley was one of the founders of both the Societas Rosicruciana in Anglia, an esoteric branch of Freemasonry, and the Society of Eight, the inner core of the SRIA. From there the cipher manuscript could easily have passed into the hands of westcott or Mathers, both of whom were members of both groups.

There is another remote possibility. Sometime during the mid nineteenth century  the Grand Secretary of the grand Lodge of England paid a fraternal visit  to the Morgenrothe lodge. It is possible that which he was there he  picked up the Cypher manuscript, maybe as a result of checking up on aspects of Masonic orthodoxy within the lodge. From there it may have been taken back to England and found its way into the archives or individuals of the SRIA since Hockley, Westcott, John Yarker and others were active collectors of rites and rituals.