The Kingdom of Ireland was a monarchy on the island of Ireland that was a client state of England and then of Great Britain. It existed from 1542 to the end of 1800. It was ruled by the monarchs of England and then of Great Britain, and was administered from Dublin Castle by a viceroy appointed by the English king: the Lord Deputy of Ireland. Aside from brief periods, the state was dominated by the Protestant English minority. The Protestant Church of Ireland was the state church. The Parliament of Ireland was composed of Anglo-Irish nobles. From 1661, the administration controlled an Irish army. Although styled a kingdom, for most of its history it was, de facto, an English dependency. This status was enshrined in Poynings' Law and in the Declaratory Act of 1719.

The Kingdom of England was a sovereign state on the island of Great Britain from the early 10th century, when it emerged from various Anglo-Saxon kingdoms, until 1 May 1707, when it united with Scotland to form the Kingdom of Great Britain, which would later become the United Kingdom. The Kingdom of England was among the most powerful states in Europe during the medieval and early modern colonial periods.