"The 5=6 ritual appeared. Mathers seems to have taken elements given by this mysterious adept from Liege and fused it with rituals from SRIA. At the same time there came the fantastic Z documents, which superimposed a magical technique over the outer order and gave a formula that turned a somewhat dry masonic ritual into something that could be used to charge a talisman or get a spirit to physical manifestation. There is also the fairly cryptic Man, Macrocosm paper which gives a fairly powerful introduction to the Sphere of Sensation. We also see Book T, which was an inspired description of the Tarot.
But we cannot be sure how much of this material or genius belonged to Mathers, or how much was a cut and paste from Lux E Tenebris. Certainly the 5=6 is nothing like what Mathers had written before, or would write again. Mathers or Tenebris? Or again was someone else involved? We know that other adepts were also inspired at this time. Take for example the design of the Vault. Mathers' rite does not say much about it, other than recount the official material from the Manifestos. Yet the person who seems to be writing the most about the Vault is Westcott. It is his material, based on a lecture, that remains in both the SM and AO."- Nick Farrell, The Genius of the Golden Dawn
(Hermetic Virtues, Vol. 1, No. 3)