Janus was a Roman god and is portrayed with two heads, one looking forward and the other looking back. In due course he became the symbol of New Year, with one head looking at the year gone by and the other looking at the New Year.
Janus is also from where the first month of the year, January, gets its name.
Janus, in ancient Rome was known as the god of the gates, whose one face saw the people who came into the house and other looked at those who were in it. Janus symbolized transition, from past to future. Janus was in the middle in every divide, be it of civilizations, age or seasons or coming-of-age.