evidence: Travelling inland from its mouth, the River Congo holds many stories of slavery, colonialism and independence. Democratic Republic of Congo – The River Congo has always inspired reverence. [...] Dispatched on a second voyage by the Portuguese king two years later, Cao forged friendly relations with the manikongo, the ruler of the Kingdom of Kongo, an independent state founded in the late-14th century. The kingdom included a lengthy section of the river and stretched hundreds of miles inland to include parts of today’s Democratic Republic of Congo (Congo), Angola, Republic of Congo and Gabon.