After initially staying near the bodhi tree in enlightenment for seven weeks, the Buddha then started to move about and preach the Buddhist Dharma.
After first teaching the nagas (earth guardian serpents), the Buddha taught his former cohort of ascetics in a park near the city of Sarnath.
In starting to preach, the Buddha was said to have started to “turn the wheel of the Dharma,” thereby helping others to find the path of enlightenment.
Since the Buddha started this teaching in a park inhabited by deer (near Sarnath), the image of the eight-pointed wheel surrounded by deer is commonly used to represent the Eightfold Path of the Buddha’s teachings.