In the ninth year of the reign of Akhenaten, he declared the traditional supreme God Aten to be the only God of Egypt with himself as the sole communicator to Aten, kind of like an early Pope. This early attempt at monotheism failed after about 20 years and Egypt returned to their traditional polytheistic religion.
About the image: Akhenaton and Nefertiti seated, holding 3 of their daughters, under the rays of the sun god Aten giving Ankh-symbols to them (Picture provided by ArchaiOptix).