Roger II Mosaic Detail from the Martorana in Palermo

1.  Roman law began to influence and shape secular and canon law circa 1140.  This was the Birth, the "Big Bang" of the Ius commune in the first half of the twelfth century.

2.  From the start Roman law was not simply or only incorporated into  non-Roman law texts;  jurists adapted Roman law institutions, concepts and principles to the needs of local communities.

3. Roman law becomes a "practical science" in the Aristotelian sense of the term.

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