In Lisbon, Portugal, a pivotal declaration marked the end of the Iberian Union and the rule of the Philippine Dynasty when João IV was acclaimed king. The Iberian Union had existed for 59 years, following the succession crisis in Portugal after the death of King Sebastian I and the subsequent Philip II of Spain's claim to the Portuguese throne. Over the years, the union was met with resistance and resentment among the Portuguese, who faced heavy taxation, military conscription, and a lack of representation in governance. The biggest stirrings of discontent began to crystallize into a concerted effort for independence, fueled by a mix of nationalistic fervor and the desire for local governance.

Amidst the political climate, João IV, a member of the House of Braganza, emerged as a leading figure advocating for freedom. His ascension was not only a personal gain but also a broader rallying point for those who wished to see an end to Spanish interference in Portuguese affairs. The proclamation in December led to the rebellion against Spanish authority and the establishment of a new dynasty, with celebrations echoing across the country as public sentiment shifted towards national pride and autonomy. This royal acknowledgment was a key moment in the resurgence of Portuguese identity and governance.

João IV's ascendance marked the restoration of the Portuguese monarchy and strengthened Portugal's distinct cultural and political identity, following years of external rule. This moment catalyzed military and diplomatic efforts to further cement Portugal’s sovereignty, setting the stage for subsequent conflicts, and lasting impacts on Portuguese colonial ambitions around the world. The successful acclamation also showcased the enduring spirit of national autonomy that characterized the Portuguese fight against foreign rule.