Start with public policy.
How many public laws conform to religious laws/moral code?
How many of those laws actually originated from non-Christian legal systems, such as Roman law, Celtic law and so on?
How many public policies conform to astrological laws/moral code?
Does Roman law count?

The astrology was greco-roman.
(I'm seriously asking, I can't think of a single one)
I found this reference on googling "roman law influence on western civilization".
Apparently the whole idea of precedants etc ...
Franz Wieacker, The Importance of Roman Law for Western Civilization and Western Legal Thought, 4
B.C. Int'l & Comp. L. Rev. 257 (1981),
http://lawdigitalcommons.bc.edu/iclr/vol4/iss2/these "roots" in the modern legal systems of the European-Atlantic world.
The large amount of material which has been handed down to us and which
we encompass in the term "Roman law" forms a constituent part of the occidental
world.
It formed nations and legal systems and allowed them to
become aware of their own identity. It provided the basis for the rational
character of the systems and the legalism of the western nations. Further, even
the
very principle of settling social and economic conflicts not only by force,
authority or compromise, but also by the application of general conceptual
rules - which is the characteristic feature of western legal thought - became
possible on the basis, and perhaps only on the basis, of Roman law, or what
was thought to be Roman law. In reality, to use the fine words spoken
...
Koschaker, Roman law is
a vinculum iuris quo totims occidms contin,tur [a bond of law by which so often the
West is held together, ,d. j.I
Although they developed along different lines, the two great legal systems of
the Western world have this rational character in common, I am referring, of
course, to a well-known dualism. On the one hand, there are the legal systems
of the European continent and of Latin America. These systems are essentially
characterized by the great codifications. In the first place, there are the Latin
codes modeled after the Napoleonic codes. In the second place, there are the
Central-European codes of Austria, Germany and Switzerland and their
followers in other countries. Within the boundaries of the United States we
find a well-known example of this legal system in the Code of Louisiana. On
the other hand, there is the common law of the Anglo-American countries
which, if you will allow me to speak as a continental legal historian, I regard as
an historical unity.
On the whole, this system is characterized by a unique
court system and, despite the growing importance of statute law, by the
dominance of calle law based On the principle of the binding force of
precedents.2[/quote]