Just as there exists NO mention on the Priory of Sion prior to 1956 with Plantard 's planted Dossiers Secrets, there is NO mention of Rosicrucianism before the 17th century appearance of three Rosicrucian Enlightenment manifesto pamphlets, which presented insight into "universal information" combining mystical Christianity, alchemy, Hereticism, and the Kabbalah.
The "rose" and Jean Cocteau's included portrait staring at the viewer in the series of Cocteau's mural panels in London's Church of Norte Dame de France does not prove the he was Grandmaster or that the Priory of Sion actually exists outside of Plantard's creation.
All of these supposed connections of Templars, Rosicrucians, Priory of Sion, Poussin, Teniers, Shugborough Shepard's folly, and so on are more like a crazy quilt fabricated with random patched together facts than a "big puzzle where all the pieces fit"
When one takes "care" to research real actually documented history and events, one will realize that these "puzzle pieces" do not fit that well at all.