John Wesley (1703-1791) was an Anglican cleric and Christian theologian. Wesley is largely credited, along with his brother Charles Wesley, with founding the Methodist movement which began when he took to openair preaching in a similar manner to George Whitefield. In contrast to George Whitefield's Calvinism (which later led to the forming of the Calvinistic Methodists), Wesley embraced Arminianism. Methodism in both forms was a highly successful evangelical movement in the United Kingdom, which encouraged people to experience Christ personally. Wesley helped to organise and form societies throughout England, Scotland, Wales and Ireland; small groups that developed intensive, personal accountability, discipleship and religious instruction among members. His great contribution was to appoint itinerant, unordained preachers who travelled widely to evangelise and care for people in the societies. Young men who acted as their assistants were called "exhorters" who functioned in a similar fashion to the twelve apostles after the ascension of Jesus. Under Wesley's direction, Methodists became leaders in many social justice issues of the day, including the prison reform and abolitionism movements.