Under which monarch was Wales formally united with England?

Henry VIII is the monarch you need to remember when thinking about the formal union of Wales and England. Before Henry VIII, Wales had been under English control since Edward I conquered it in the 13th century, but it wasn't formally part of England. Welsh laws and customs still existed. Henry VIII, wanting to consolidate his power and create a more unified kingdom, passed the Laws in Wales Acts in the 1530s. These acts essentially integrated the Welsh legal system with the English one, abolished Welsh laws, and gave Wales representation in the English Parliament. So, while England had influence in Wales for centuries prior, it was Henry VIII who legally and formally united the two countries. Elizabeth I, Edward VI, and James IV reigned later and didn't play a role in this particular unification. It's a common mistake to think of Elizabeth I because she was a powerful monarch, but the key event happened earlier during Henry VIII's reign.