British occultist, astrologer, author and translator; the founder of the mystical organization The Golden Dawn.
Mathers met Moina Bergson in the British Museum where she was painting artworks of the Egyptian deities. She became the first Golden Dawn initiate at the time when he founded it along with two other mystics in 1888, London and two years later, she became his wife. It said to be a celibate marriage: he was the Magician and she, the High Priestess.
In the fall of 1891 Mathers went to Paris, meeting with occult adepts called the Secret Chiefs, who provided rituals for a secret Inner Order, revealing secrets of the Universe and magical powers. The Golden Dawn inner circle included Annie Horniman, Florence Farr and Maud Gonne. Horniman put Mathers to work cataloguing her father’s library and when she got her inheritance in August 1893, she supported the couple as a patron to Moina’s art.
With metaphysical fervor, the Golden Dawn taught “the secrets of the Adepts,” utilizing clairvoyance, astral projection, table-tapping, ouija boards, the pendulum and possibly the disciplines of tantra. The majority of their papers were written in 1891-93 (during a Neptune-Pluto conjunction), in which they established the rituals and techniques of the Golden Dawn. He died in November 1918 in Paris.
Link to Wikipedia biography