The Doom Book. Despite the fact that the Doom Book attempts to mix in Christian conceptions of the law, it's largely a collection of pre-existing legal customs of the Saxons and their germanic ancestors. This independence of secular law from canonical law was only further boosted by Henry II's creation of the "true" common law system, which incidentally further reduced the power of canonical law. While the death of Archbishop Becket would later curb some of Henry II's attempts to reduce the Church's power, in the long run, the system of stare decisis and independent judicial reasoning (the laws under this system originated from the bench from judges acting under the authority of the monarch). This is, of course, ignoring the fact that the Anglican church did not even exist during the reign of Henry II.
The relationship between secular and canonical law was often messy and complicated, especially in England, and you just painted it with a very broad brush. Don't do so.
Also, I am assuming you meant to put a "the" in between the they're and only parts of your sentence. So to answer that; no they are not the ONLY societal norms but they are the ones that can get you sent to jail for not conforming to, which thus makes them the most integral and severe.
Then you assume wrong. I said, "laws are not only societal norms". I'm challenging the very fundamental assumption you made, which is the idea that laws originate from only societal norms and not other more abstract thought processes (such as ethical reasoning or policy analyses).
