From c. 1390 to 1862, it was an independent state. From 1862 to 1914, it functioned intermittently as a vassal state of the Kingdom of Portugal.[12] In 1914, following the Portuguese suppression of a Kongo revolt, Portugal abolished the titular monarchy. From c. 1390 to 1862, it was an independent state. From 1862 to 1914, it functioned intermittently as a vassal state of the Kingdom of Portugal.[12] In 1914, following the Portuguese suppression of a Kongo revolt, Portugal abolished the titular monarchy. From c. 1390 to 1862, it was an independent state. From 1862 to 1914, it functioned intermittently as a vassal state of the Kingdom of Portugal.[12] In 1914, following the Portuguese suppression of a Kongo revolt, Portugal abolished the titular monarchy. From c. 1390 to 1862, it was an independent state. From 1862 to 1914, it functioned intermittently as a vassal state of the Kingdom of Portugal.[12] In 1914, following the Portuguese suppression of a Kongo revolt, Portugal abolished the titular monarchy.