Ancient lawgiver's work pieced together (6)
I believe the answer is:
mosaic
'work pieced together' is the definition.
(work made from many pieces)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(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" .)