This painting depicts the Hindu god Shiva as Tripuravijaya, Victor of the Three Cities.  He is relaxing in a contrapposto pose after having completed the feat of destroying the cities of the three demons with a single arrow.   This image was taken from a 10th century bronze sculpture from the Chola Empire which ruled southern India c. 850-1250 AD.  The sculpture is missing the bow and arrow which is part of the composition, so wasn’t included in the painting.