World War II: Australian forces launched an assault on Sattelberg, New Guinea, against Japanese forces, initiating the Battle of Sattelberg.

World War II or the Second World War was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were tried for war crimes.

Sattelberg, also spelt Satelberg, is a village on the Huon Peninsula, in Morobe Province, Papua New Guinea. The village is set on a peak about 900 metres (3,000 ft) above sea level, and dominates the area, with Finschhafen below. A Lutheran mission was founded by Johann Flierl in 1892, when the area was part of German New Guinea. As part of the settlement of World War I in 1919, responsibility for administering the territory was passed to Australia. In 1921, the Australian government gave permission for the German missionaries to remain, but placed the Lutheran Church of Australia in control of the mission. In the early 1930s, German influence was re-established as the Lutheran Church of Australia relinquished its control of the mission.

The Battle of Sattelberg took place between 17 and 25 November 1943, during the Huon Peninsula campaign of the Second World War. Involving forces from Australia, the United States and Japan, the fighting centred on the Sattelberg mission station which was situated atop a hill about 900 metres (3,000 ft) above sea level, approximately 8 kilometres (5.0 mi) inland from Finschhafen, New Guinea. Following the Australian landing at Scarlet Beach a large force of Japanese had retreated inland towards Sattelberg. The Japanese, holding the high ground, subsequently threatened the Australian lines of communication as they advanced south towards Finschhafen. The Australian 26th Brigade was tasked with capturing the mission to neutralise this threat. Over the course of 10 days they advanced west from Jivevaneng up the southern approaches to the mission, reducing the Japanese position with armour, artillery, and air support. The Japanese finally abandoned Sattelberg and withdrew north to Wareo, having suffered heavy casualties and running low on supplies.