July 10 in Military History — On This Day

Battle of Northampton

Warwick led a Yorkist army south from Calais and confronted the royal Lancastrian army entrenched near Northampton. Treachery decided the battle — Lord Grey of Ruthin, commanding part of the Lancastrian line, lowered his men's weapons and helped the Yorkists clamber over the defences. The Lancastrian position collapsed in minutes. King Henry VI was captured once again, and the Duke of Buckingham was killed.

Northampton delivered Henry VI back into Yorkist hands and set the stage for Richard of York to formally claim the throne through the Act of Accord — which made York heir apparent over Henry's own son. It was the high-water mark of Yorkist political success before the catastrophe at Wakefield.

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Battle of Huamachuco

In the high Andes, Cáceres's guerrilla army — the 'Breñeros' who had waged a brilliant mountain resistance for two years — came close to victory at Huamachuco before running out of ammunition and being routed by the Chileans, who executed many prisoners afterward.

Huamachuco broke the back of the Peruvian resistance and cleared the way for the peace. Later that year Peru signed the Treaty of Ancón, ceding Tarapacá to Chile and ending the war.

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Battle of Britain

The first major campaign fought entirely by air forces. The Luftwaffe attempted to destroy the RAF as a prelude to Operation Sea Lion — the invasion of Britain. RAF Fighter Command, using radar and the Spitfire and Hurricane, inflicted unsustainable losses. When Hitler shifted attacks to bombing London (the Blitz), it gave RAF airfields time to recover. Germany never achieved air superiority.

The first defeat of the Wehrmacht. Hitler indefinitely postponed Operation Sea Lion and turned east toward the Soviet Union. Churchill's words — 'Never in the field of human conflict was so much owed by so many to so few' — honored the 544 RAF pilots who died. Radar proved decisive in modern warfare for the first time.

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⚔️📍 Sicily, Italy1943

Operation Husky — Allied Invasion of Sicily

160,000 Allied troops landed on Sicily in the largest amphibious operation to that point in the war, involving 3,000 ships. Despite poor coordination and scattered airborne drops, the landings succeeded against Italian defenders who largely chose not to fight.

The Sicily campaign convinced Italian generals to overthrow Mussolini and led directly to Italy's armistice — opening the 'soft underbelly' of Europe to Allied invasion.

Outcome

Allied victory in 38 days; Mussolini overthrown