Aker was an ancient earth-god in
The two lions were called Sef and Duau, which means "Yesterday" and "Today" respectively.
As Egyptians believed that the gates of the morning and evening were guarded by Aker, they often placed statues of lions at the doors of their palaces and tombs. This was to guard the households and tombs from evil spirits and other malevolent beings. Sometimes they gave these statues the heads of men and women. The Greeks called this class of statuary, "Sphinxes."