On 24 September 1973 history was made in Africa. The first sub- Saharan African nation unilaterally declared its sovereignty from European colonialism following a protracted armed struggle. Most African nations gained their independence from colonial powers by negotiation and peaceful transfer of authority. True enough, this transfer was sometimes linked with prolonged periods of demonstrations, strikes, and nationalist propagandizing, but with the exception of Algeria (and perhaps Ethiopia) there were no wars of national liberation which led to a declaration of independence until Guinea-Bissau. The implications of this move are immense.
Lobban, R. (1974). Guinea-Bissau: 24 September 1973 and beyond. Africa Today, 21(1), 15-24.