Arthur Featherstone Marshall (1818 – 14 December 1877) was an English Anglican priest who converted to Roman Catholicism in the 1860s.

Marshall abandoned his curacy at Liverpool to become a Roman Catholic in the early 1860s. He subsequently published satirical (mostly pseudonymous) material on the Anglican principle of comprehensiveness and a trenchant criticism of opponents of the First Vatican Council

First Vatican Council

The First Vatican Council was convoked by Pope Pius IX on 29 June 1868, after a period of planning and preparation that began on 6 December 1864. This twentieth ecumenical council of the Roman Catholic Church, held three centuries after the Council of Trent, opened on 8 December 1869 and adjourned...

, especially Old Catholics. Specific Anglican tenets he singles out for attack include the Branch theory

Branch theory

The Branch Theory is a theological concept within Anglicanism, holding that the Roman Catholic Church, the Eastern Orthodox Church and the Anglican Communion are the three principal branches of the One, Holy, Catholic, and Apostolic Church.-Theory:...

 and the sacramental validity of Anglican ministry

Anglican ministry

The Anglican ministry is both the leadership and agency of Christian service in the Anglican Communion. "Ministry" commonly refers to the office of ordained clergy: the threefold order of bishops, priests and deacons. More accurately, Anglican ministry includes many laypeople who devote themselves...

 and holy orders.

His elder brother Thomas William Marshall

Thomas William Marshall

Thomas William Marshall was a Roman Catholic convert from Anglicanism during the Tractarian controversies. In 1847 he became the first inspector of Catholic Schools in Great Britain. He resigned in 1860 after a controversy due to a pamphlet he wrote critical of Anglican missionary work.-...

(1818–1877) was also a Roman Catholic convert and controversialist .