1) Christianisation 
Christianization (or Christianisation) is the conversion of individuals to Christianity or the conversion of entire peoples at once. It may also refer to the forced imposition of a Christian society. Various strategies and techniques were employed in Christianization campaigns from Late Antiquity and throughout the Middle Ages: evangelization by m...
• (n.) The act or process of converting or being converted to a true Christianity.
Chris`tian·i·za'tion noun The act or process of converting or being converted to a true Christianity. 
Christianisation noun conversion to Christianity