Question: What war involved both the Battle of Peleliu and the Gothic Line?

Context paragraphs:
Gothic Line order of battle: Gothic Line order of battle is a listing of the significant formations that were involved in Operation "Olive", the Allied offensive on the Gothic Line in northern Italy, August–September 1944, and in the subsequent fighting in the central Apennine mountains and on the plains of eastern Emilia–Romagna up to April 1945.

Battle of Rimini (1944): The Battle of Rimini took place between 13 and 21 September 1944 during Operation "Olive", the main Allied offensive on the Gothic Line in August and September 1944, part of the Italian Campaign in the Second World War.  Rimini, a town on the Adriatic coast of Italy, anchored the Rimini Line, a German defensive line which was the third such line forming the Gothic Line defences.

Gothic Line: The Gothic Line (German: "Gotenstellung" ; Italian: "Linea Gotica" ) was a German defensive line of the Italian Campaign of World War II.  It formed Field Marshal Albert Kesselring's last major line of defence along the summits of the northern part of the Apennine Mountains during the fighting retreat of the German forces in Italy against the Allied Armies in Italy, commanded by General Sir Harold Alexander.

Battle of Gemmano: The Battle of Gemmano was fought between the German and Allied forces in World War II.  It was part of the Allies' Operation Olive, the offensive in August 1944 on the Gothic Line, the German line of defence in the Apennines in northern Italy.  It consisted of a series of four British attacks between 4 September to 15 September 1944, on the German defences in and around the village of Gemmano.  The village itself was taken on 9 September during the second attack, two more actions being required to take the surrounding area.  Fighting was heavy, and the Battle of Gemmano has been called the "Cassino of the Adriatic" by some historians.

Battle of Peleliu: The Battle of Peleliu, codenamed Operation Stalemate II by the United States military, was fought between the U.S. and the Empire of Japan during the Mariana & Palau Campaign of World War II, from September to November 1944, on the island of Peleliu.

Flagstaff War: The Flagstaff War – also known as Hōne Heke's Rebellion, the Northern War and the First Māori War – was fought between 11 March 1845 and 11 January 1846 in and around the Bay of Islands, New Zealand.  The conflict is best remembered for the actions of Hōne Heke who challenged the authority of the British by cutting down the flagstaff on Flagstaff Hill (Maiki Hill) at Kororāreka, now Russell.  The flagstaff had been a gift from Hōne Heke to James Busby, the first British Resident.  The Northern War involved many major actions, including the Battle of Kororāreka on 11 March 1845, the Battle of Ohaeawai on 23 June 1845 and the siege of Ruapekapeka Pā from 27 December 1845 to 11 January 1846.

Peleliu: Peleliu (or Beliliou) is an island in the island nation of Palau.  Peleliu forms, along with two small islands to its northeast, one of the sixteen states of Palau.  The island is noted as the location of the Battle of Peleliu in World War II.

Battle of Nájera: The Battle of Nájera, also known as the Battle of Navarrete, was fought on 3 April 1367 near Nájera, in the province of La Rioja, Castile.  It was an episode of the first Castilian Civil War which confronted King Peter of Castile with his half-brother Count Henry of Trastámara who aspired to the throne; the war involved Castile in the Hundred Years' War.  Castilian naval power, far superior to that of France or England, encouraged the two polities to take sides in the civil war, to gain control over the Castilian fleet.

Roman switch line: The Roman switch line was a German line of defense during World War II in Italy branching off the Caesar C line and running north of Rome towards coast of the Tyrrhenian Sea.  The next line was Trasimene Line in central Italy which was intended to delay the Allies and allow the completion of the Gothic Line a major defensive works north of Florence.

Trasimene Line: The Trasimene Line (so-named for Lake Trasimene, the site of a major battle of the Second Punic War in 217 BCE) was a German defensive line during the Italian Campaign of World War II.  It was sometimes known as the Albert Line.  The German Commander-in-Chief (C-in-C), "Generalfeldmarschall" Albert Kesselring, used the line to delay the Allied northward advance in Italy in mid June 1944 to buy time to withdraw troops to the Gothic Line and finalise the preparation of its defenses.

Supporting paragraphs: Battle of Peleliu Gothic Line
Answer: World War II