What was the Twelve Tables impact on Ancient Rome?

Answer 1

The Law of the Twelve Tables was Rome's first written and published code of law. They were hung on boards at the forum and they were written in a simple language to make them easy to understand. They covered matters which now we would call civil and criminal law. They set punishments and procedures for trials. Prior to the Tables, there were only religious laws which priests kept secrets. The proceedings of the senate were not published. This made a lot of room for arbitrary use of power and abuse. Now Roman citizens had a clear set of rules.

Answer 2

They were the first Roman written laws. Prior to them, the aristocrats held the laws in their heeads, and so the masses had to consult them and so became their clients and became dependent on them and had to support them politically and financially in return. Written law later proliferated as complexity and legal precedent set in, and the infection spread until today the legal system is overblown with endless variations of law and game playing by an ever-growing mass of practitioners who make a handsome living out of it.