When did Michael Collins go to prison and why?

Michael Collins was imprisoned in 1922 during the Irish Civil War. He was a prominent leader in the fight for Irish independence but was captured by anti-Treaty forces due to his support for the Anglo-Irish Treaty, which established the Irish Free State. His imprisonment was a consequence of the deep divisions within the Irish nationalist movement over the treaty. Collins was released later that year, but the civil strife continued until his death in 1922.