when did this siege end?
20 August 1346
Siege of Aiguillon
20 August
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) in which country did this take place? France who was the leader from the first group you mentioned earlier? John, Duke of Normandy and who was the leader from the second group mentioned earlier? Ralph, Earl of Stafford
wiki:23321428
Siege of Aiguillon [SEP] French withdrawal
On 29 July Philip VI called an "arrière-ban" for northern France at Rouen. On 7 August the English reached the Seine. Philip VI sent orders to Duke John insisting that he abandon the siege of Aiguillon and march his army north. Edward III marched south east and on 12 August his army was from Paris. On 14 August, Duke John attempted to arrange a local truce. Lancaster, well aware of the situation in the north and in the French camps around Aiguillon, refused. On 20 August, after over five months, the French abandoned the siege and marched away in considerable haste and disorder.