Diogo Cão, a prominent Portuguese sea captain and explorer, embarked on a pivotal voyage along the west coast of Africa in the late 15th century. As part of Portugal's broader strategy to explore and establish trade routes, Cão set sail towards the southern regions of Africa. His expedition was a response to an increasing interest in the geographical and commercial opportunities that Africa presented. On reaching the mouth of the Congo River, Cão not only marked a significant navigational achievement but also laid the groundwork for future European exploration of the African interior.

During this journey, Cão planted a padrão (a stone monument) at the mouth of the river, claiming the territory for Portugal. This act symbolized European imperial ambitions in Africa, characterizing a time when European powers sought to extend their reach and control over vast regions. The mouth of the Congo River was particularly important, as it served as a gateway to one of the continent's largest river systems, which would later facilitate trade, including the slave trade, and increased European interests in the region.

Cão's exploration contributed to a growing understanding of the African coastline and acted as a catalyst for subsequent expeditions by other Portuguese navigators. His findings were documented and used by following explorers who sought to map and exploit the resources of Africa. The repercussions of Cão's journey began a trend of European engagement with Africa that transformed the continent's socio-economic landscape and directly impacted the indigenous populations in the centuries to follow.