A civilization grows in relation with other civilizations, and it exists only in connection with others. Civilizations make self-development by affecting each other. To understand the development of human civilizations, it is important to observe their connections and particularly to focus on the civilizations that worked to mediate other civilizations. The civilizations held by nomads, traders or marine people played such role. The aim of this writing is to give a fresh perspective into the civilization study by introducing a concept of ‘Medium Civilization’. What is human civilization? In order to explain it clear, we need to see ‘medium civilization’ that enabled civilizations to form and develop.