After the July 1921 ceasefire, Collins and Arthur Griffith were sent to London by Éamon de Valera to negotiate peace terms. The resulting Anglo-Irish Treaty established the Irish Free State but depended on an Oath of Allegiance to the Crown, a condition with which de Valera and other republican leaders had difficulty reconciling. Collins viewed the treaty as offering "the freedom to achieve freedom", and persuaded a majority in the Dáil to ratify the treaty. A provisional government was formed under his chairmanship in early 1922 but was soon disrupted by the Irish Civil War, in which Collins was commander-in-chief of the National Army. He was shot and killed in an ambush by anti-Treaty forces on 22 August 1922.