Sun married Sanjna, the Daughter of Vishwakarma the Celestial Creator and architect of the Universe. When she left the Sun due to His severe Rays, Chhaya entered in place of Sanjna and got 2 Sons named Savarni and Shani from the Union with the Sun. One day when Sanjna returned she was not allowed entry in her own Home.
Disappointed, she took the form of a Mare and the Sun too assumed the form of a Horse, and after meeting when they united, the two Kumaar’s Ashwini Kumaar’s or the Celestial Doctors were born. (Now you know one reason why Ashwini also depicts the Horse).
The Sun is seated on a Chariot drawn by the 7 Horses. They also represent the 7 states of Consciousness. Also the 7 Koshas (SaptaKosha), also the 7 Lokas (SaptaLoka), also the 7 Planets The Sun in its real estate is the Invisible Creative Power.