Following the Glorious Revolution, a pivotal moment in English history, William of Orange and his wife Mary II were proclaimed co-monarchs of England. The revolution arose from discontent with King James II's reign, which was marked by attempts to enhance royal power and promote Catholicism in a predominantly Protestant nation. As tensions escalated, Parliament sought to restore their authority and protect the Protestant faith, inviting William to invade. Upon successfully landing in England with an army, William’s growing support led to James's departure from the throne.

The proclamation took place at Whitehall, where both William and Mary were publicly acknowledged as co-regents. Their joint rule signified a landmark moment in English governance, as they accepted the throne with the stipulation of upholding the Bill of Rights, thereby affirming the dominance of Parliament over the monarchy. This transition represented a significant ideological shift towards a constitutional monarchy, where sovereign powers were curtailed by legal frameworks, paving the way for modern parliamentary democracy.

The period following the proclamation ushered in vital changes in governance and society. It marked the beginning of a new political alignment in England, where the state's relationship with its subjects was redefined. The subsequent establishment of policies reinforced Protestantism and limited the power of the crown, culminating in a more balanced distribution of power within the government. The legacy of William and Mary’s joint rule profoundly influenced political thought and structures, resonating through future generations.