Aker, sometimes spelled as Akar, is one of the oldest known ancient Egyptian deities. He was worshipped as the guardian of the horizons.
As the guardian of the horizons, Aker was seen as the gatekeeper for the beginning and end of each day. He existed on the boundaries. He was first depicted as a strip of land, then as a strip of land with a lion’s head on each side facing outward. Finally, this evolved into two lions or sphinxes facing away from each other.
As the Egyptians believed that Ra, the sun god, undertook a journey through the underworld each night to be reborn on the eastern horizon, Aker held a place of importance. In some instances, Aker is referred to as guiding and protecting Ra during this journey. The dead also had to undertake a journey through the underworld to be judged and hopefully found deserving of eternal life.
The dead had to ask permission from Aker to enter the underworld. As they passed, Aker would “cure” the causes of their deaths. He is also a protective deity. Supposedly he protected at least one pharaoh from the demon snakes Hemtet, Iqeru, and Jagw.
This protective aspect may be what led the Egyptians to place twin statues of lions outside of tombs and palaces. Greeks and Romans also have this tradition and some still follow it today.