What was the central issue in the conflict between henry ii and thomas becket?

The central conflict was founded on the doctrine of separation of state and church powers

Henry wanted to retain powers over the church while Thomas, once his loyal friend, upon his appointment reverted to a very odd way that surprised the king. Thomas embarked on ecclesiastical wars with the king  to enhance the powers of the church. The conflict culminated in his murder.

Ummm they were radical