Maxwell arrived in Ireland on Friday 28 April as "military governor" with "plenary powers" under Martial law, replacing Lovick Friend as the primary British military commander in Ireland. Afterwards, he set about dealing with the rebellion under his understanding of Martial law. During the week of 2–9 May, Maxwell was in sole charge of trials and sentences by "field general court martial", in which trials were conducted without defence counsel or jury members and in camera.