in which country did this take place?
France
Siege of Aiguillon
In 1345 Henry, Earl of Lancaster, was sent to Gascony in south west France
what is siege of aiguillon? It was an episode in the Hundred Years' War, began on 1 April 1346 when a French army commanded by John, Duke of Normandy, laid siege to the Gascon town of Aiguillon. which groups fought in this? French army and  Anglo-Gascon army (English Army)
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Siege of Aiguillon [SEP] Introduction
The Siege of Aiguillon, an episode in the Hundred Years' War, began on 1 April 1346 when a French army commanded by John, Duke of Normandy, laid siege to the Gascon town of Aiguillon. The town was defended by an Anglo-Gascon army under Ralph, Earl of Stafford. In 1345 Henry, Earl of Lancaster, was sent to Gascony in south west France with 2,000 men and large financial resources. In 1346 the French focused their effort on the south west and, early in the campaigning season, an army of 15,000–20,000 men marched down the valley of the Garonne. Aiguillon commands both the Rivers Garonne and Lot, and it was not possible to sustain an offensive further into Gascony unless the town was taken.