May I throw in my paltry two pennorth. I am ancient so pre internet garnered knowledge from old books and living in London there were plenty around.
In all the Holy Grail, bloodline opinions the painting Et in Arcadia Ego by Poussin seems paramount. It merely depicts the story of Icarius of Athens. Long story short the three main characters were turned into Bootes, Virgo and the star Procyon in Canis Minor, so I would assume this collection in the heavens is highly significant.I know the Goddess by various names certainly is. Dionysus sits watching and is a clear representation of the Cult of Dionysus way back in Babylon and neighbouring lands. I find most things lead back to Babylon. When the Freemasons were created by Bacon, amongst others, we have the sickle of Ceres foremost, the letter G in the logo.( Hammer and Sickle...). I think the closest reference we still have could be Zoroastrianism. The constant duality. As above so below, as below so above. Land boundaries may change but the heavens remain constant. A sky map/ farming calendar .Even Freddie from Queen, a Zoroastrian, chose Mercury for his name and wore a half white, half black outfit for his first major show. There are multiple layers of codes in all the writings but the Templars et al drew so heavily on Astronomy. Even the twins on one horse..Castor and Pollux..duality of one mortal and one immortal.At one time the line continued through the females not the male in some cultures so maybe this is why the Goddesses are paramount.
Flipping to AstroLogy I relate the worship of Lions and Bulls etc to a Timeline.e.g. the Age of Taurus = Bull,Age of Leo = the Sun/Lion.It may suggest our history is not chronologically accurate though.If each Age lasts around 2000 years we are leaving the Age of Pisces..the Fish..symbol of Christ, going into Aquarius the Water Bearer.You don't have to believe anything to observe it.
Best wishes with your research.