Ancient lawgiver's work pieced together (6)

I believe the answer is:

mosaic

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'work pieced together' is the definition.
(work made from many pieces)

I cannot understand how the rest of the clue works.

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(Other definitions for mosaic that I've seen before include "Design made of small pieces of coloured stone or glass" , "Picture/pattern in small coloured pieces" , "Design made of small pieces of colored stone or glass" , "Relating to Moses" , "Pattern of fragments" .)

I've seen this clue in The Guardian.

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