The Emperor is the rational father archetype. He is our thoughts and energy connection to reality and practicality. The unconsciousness is accessible, and appears relaxed and secure. Peace is dominant in this realm and thus he does not wear armor however his shield denotes an eagle signifying the connection with the heavens, a ruler with divine right. He is a warrior of past times, in a peaceful state today. He is the leader and father, however he is still connected with the Empress as a royal pair.
He brings permanence, and perspective – as well as stability as the figurehead of the state. The number 4 bring wholeness – four directions, corners of the earth, seasons, phases of the moon, etc. It is connected with the creation of man and the reality of being human.
Source: Jung and Tarot: An Archetypal Journey, by Sallie Nichols