Overview
The Aten, the sun-disk, is first referred to as a deity in The Story of Sinuhe from the 12th dynasty, in which the deceased king is described as rising as god to the heavens and uniting with the sun-disk, the divine body merging with its maker. By analogy, the term "silver aten" was sometimes used to refer to the moon. The solar Aten was extensively worshipped as a god in the reign of Amenhotep III, when it was depicted as a falcon-headed man much like Ra. In the reign of Amenhotep III's successor, Amenhotep IV, the Aten became the central god of Egyptian state religion, and Amenhotep IV changed his name to Akhenaten to reflect his close link with the new supreme deity.
The full title of Akhenaten's god was "The Ra-Horus who rejoices in the horizon, in his/her Name of the Light which is seen in the sun disc." (This is the title of the god as it appears on the numerous stelae which were placed to mark the boundaries of Akhenaten's new capital at Akhetaten, modern Amarna.) This lengthy name was often shortened to Ra-Horus-Aten or just Aten in many texts, but the god of Akhenaten raised to supremacy is considered a synthesis of very ancient gods viewed in a new and different way. The god is also considered to be both masculine and feminine simultaneously. All creation was thought to emanate from the god and to exist within the god. In particular, the god was not depicted in anthropomorphic (human) form, but as rays of light extending from the sun's disk.
Furthermore, the god's name came to be written within a cartouche, along with the titles normally given to a Pharaoh, another break with ancient tradition. Ra-Horus, more usually referred to as Ra-Horakhty (Ra, who is Horus of the two horizons), is a synthesis of two other gods, both of which are attested from very early on. During the Amarna period, this synthesis was seen as the invisible source of energy of the sun god, of which the visible manifestation was the Aten, the solar disk. Thus Ra-Horus-Aten was a development of old ideas which came gradually. The real change, as some see it, was the apparent abandonment of all other gods, especially Amun, and the debatable introduction of monotheism by Akhenaten. The syncretism is readily apparent in the Great Hymn to the Aten in which Re-Herakhty, Shu and Aten are merged into the creator god. Others see Akhenaten as a practitioner of an Aten monolatry, as he did not actively deny the existence of other gods; he simply refrained from worshipping any but the Aten.
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