1679-1735. Organizer and first leader of the New Baptists, or Brethren. This group, founded in 1708, in 1871 adopted the name German Baptist Brethren, but its main body today is known as the Church of the Brethren.* Born in Schriesheim, Germany, of Reformed parents, and a miller by trade, Mack was attracted to radical Pietism, and became a close associate of one of the leaders of that movement, E.C. Hochmann* von Hochenau. Mack accompanied Hochmann on some of his preaching missions. Due to governmental persecution of Pietists, Mack sold his mill and moved to Schwarzenau in the county of Wittgenstein. There eight Pietists under the leadership of Mack and because of Anabaptist influence became convinced that complete fidelity to the NT required the actualization of the gathered community of believers. The Brethren were born. Mack shepherded the body through persecution, resettlement, and finally to Pennsylvania. The first party reached the New World in 1719; the second, including Mack, arrived in 1729. Some 250 reached 's land. Mack provided leadership until his death.
Mack's leadership role is ably exemplified in his two writings. The shortened titles of the works are Basic Questions (1713) and Rights and Ordinance (1715). Total obedience to, including the constituting of the visible brotherhood community, was the key concept. English translations of Mack's two writings are in D.F. Durnbaugh (ed.), European Origins of the Brethren (1959).
, Jr. (1715-1803) followed in his father's footsteps, guiding the Brethren in his adult life.