This had the effect of changing the entire society as people intermarried and adopted the ways of the Europeans. So instead of native tribal dynasties, a feudal system was established to facilitate payments where previous commercial transactions were conducted using only the barter system.
The Normans were able to introduce certain legal concepts such as prison reforms for common criminals only in areas under their control. The Norman legal and political systems was at best patchy, uneven and confusing. Like most other areas of Northern Europe, the Irish legal system prevailed in the areas not controlled by the Normans. This Irish legal system was known as the Brehon Law (brehon means judge in the Irish language) and co-existed with the Normal system after the invasion, took a resurgence during the thirteenth century and went on until around the seventeenth century. Early Irish law during this period was a collection of statutes and these were not written down but in oral traditions governing everyday life. Laws were more inclined towards civil aspects rather than a criminal code to regulate inheritance, property and contracts in a hierarchical society but they also provided fines for the criminals.
Early Irish traditional laws reflected pre-Christian practices and beliefs which were often in conflict with Canon Laws during the early Christian period. In other words, it was an odd mixture of secular laws existing in parallel with Christian influences with one odd feature which was the use of surety to compel compliance with a legal decision. It is generally agreed among historians that old Irish law was often inconsistent due to the mixing of old laws with the dictates of the Church as well as forced adaptation and innovation during that time into the legal system. However, there were two recognized schools of thought as far as Irish laws were concerned and these are the Bretha Nemed and the