Hywel Dda was a notable king of Deheubarth, a region in Wales, who ruled during the 10th century. He is best known for unifying various Welsh kingdoms and promoting the codification of laws, which became known as the Laws of Hywel Dda. His reign is often seen as a time of relative peace and prosperity in Wales. Hywel Dda's legacy includes the establishment of a legal system that influenced Welsh law for centuries. He is also remembered for his support of the Celtic Church and the promotion of culture and education. His contributions have made him a significant figure in Welsh history.