. . . . .In ancient Egyptian mythology this is called a "triad" a group of three gods that make up a family unit.

In this case, it is the triad from the ancient city of Memphis. It is made up of the creator god, Ptah on the left and his wife the protector goddess, Sekhmet on the right.

In the middle, should be their son Nefertum, but he has been replaced by the great king, Ramesses II.

In essence what we see here is Ramesses proclaiming himself as the son of the great gods of Memphis.