The Kingdom of Ireland was a state that existed from 1542 until 1800. It was established when the King Henry VIII declared himself King of Ireland, transforming the previous Lordship of Ireland into a kingdom. The kingdom was characterized by a complex relationship with England, leading to various conflicts and political changes over the years. In 1800, the Act of Union merged the Kingdom of Ireland with the Kingdom of Great Britain, creating the United Kingdom of Great Britain and Ireland. This union aimed to strengthen political ties and control over Ireland, but it also sparked significant resistance and calls for Irish independence in the following centuries.