During the Middle Ages the Christianization of the Germanic people and the formation of stable kingdoms replaced the tribal structures. The tribes merged to form the Germanic race sharing the same identity, language, culture and many similar physical characteristics. The first Christian religion of Germany was Roman Catholic but in 1517 Martin Luther initiated the Protestant Reformation which resulted in the whole of Northern Europe, with the exception of Germany, came under the influence of Protestantism. Protestant reform groups emerged including the Lutherans and Calvinists.
