This essay will assess how the processes of mission and Christianization have changed the Church, its theology and practice in the past, and continue to do so in the present. Three specific examples of change will be considered, two historic and one contemporary. First, the rejection of Old Testament ritual laws by the Apostolic Church in order to welcome Gentiles into the Church will be examined. Second, an example of adaptation from the period of the conversion of the Anglo-Saxons will be considered in relation to blood feud. A third example will be the contemporary practice of “Breakfast Church” as a tool of mission today. In each case the extent of change to theology and practice will be considered.