From 1911 to July 1914, German and British diplomats held quiet negotiations about what to do with Portuguese Angola. The discussions assumed Portugal's colonial grip was weakening and that the colony might be ripe for partition. Under the proposed arrangement, most of Angola would pass to Germany. A German lobbying organization called the Angola-Bund, founded in 1912, promoted the takeover openly. Portugal, aware of the threat, had already begun reinforcing its southern Angolan border before the war broke out in August 1914. When hostilities commenced in Europe, the border between German South West Africa and Angola remained technically open. Germany hoped to use it as a supply corridor for food and potentially arms. The Portuguese colonial government, however, proved hostile to German trade and interned several German nationals. The open border became a fault line.

The first serious incident came on October 19, 1914. A German military column crossed into Angola without Portuguese permission and was confronted by Portuguese troops at Naulila. Three German officers were killed. The Portuguese regarded it as a justified response to an unauthorized incursion; the Germans called it a provocation. Twelve days later, German troops armed with machine guns launched a surprise attack on the small Portuguese outpost at Cuangar, killing two officers, a sergeant, five soldiers, and one civilian. The assault became known as the Cuangar Massacre. These were not the large-scale engagements of the Western Front -- they were small, violent encounters in remote outposts, fought by colonial soldiers far from the capitals that had sent them.

On December 18, 1914, the campaign reached its climax. Major Victor Franke led a German force of 2,000 men against Portuguese positions at Naulila. The Portuguese resisted stubbornly but were outgunned. When the fighting ended, 69 Portuguese soldiers lay dead, including three officers, with 76 wounded and 79 taken prisoner. German losses were lighter: 12 dead and 30 wounded, though ten of those wounded were officers, a disproportionate toll that reflected the close-quarters nature of the combat. After the battle, the munitions magazine at the Portuguese base of Forte Rocadas exploded, forcing a further withdrawal. The Portuguese abandoned the entire Humbe region of southern Angola, retreating northward. For months, German forces occupied a strip of Portuguese colonial territory with impunity.

Portugal and Germany did not formally declare war until March 9, 1916 -- more than a year after the fighting in Angola had effectively ended. On July 7, 1915, Portuguese forces under General Pereira d'Eca reoccupied the Humbe region. Two days later, German forces in South West Africa surrendered to a South African-led campaign, ending German colonial rule in the territory entirely. The irony was sharp: the border conflict that had consumed lives on both sides became moot when the larger war swept away the German colony altogether. Through September 1915, the Portuguese continued operations in southern Angola -- but these were directed not at Germans but at local communities who had resisted colonial rule, some of whom had acquired German firearms during the fighting. The campaign in Angola was over, but the colonial occupation it was fought to preserve would endure for another sixty years, until Angola's independence in 1975.