According to Aleister Crowley, the last three Aeons within the system of Thelema have been (1) the Aeon of Isis, (2) the Aeon of Osiris, and (3) the current Aeon of Horus which began in 1904 with the writing of The Book of the Law
Not all Thelemites believe in a clear succession of Aeons. Sometimes Crowley compared the Word of Horus with other formulas, whose reigns appear to overlap with the Aeon of Osiris and/or Isis. The first Aeon of Isis was maternal, where the female aspect of the Godhead was revered due to a mostly matriarchal society and the idea that "Mother Earth" nourished, clothed and housed man closed in the womb of Matrix. The classical and medieval Aeon of Osiris is considered to be dominated by the paternal principle and the formula of the Dying God. The modern Aeon of Horus is portrayed as a time of self-realization as well as a growing interest in all things spiritual, and is considered to be dominated by the principle of the child. 
