Many various factors, including religion, have an influence on the giving of names to children. After the advent of Christianity in Europe, a lot of personal names from the Old Testament, as well as those of holy persons, came into use. In the countries where Germanic races used to live, the domestic base of the names was the Germanic one. This was the case also in the Netherlands and Belgium. The Reformation and the counter-reformation had a big influence on the giving of names among the Catholics and the Protestants. To find out if there was still an influence of the religion on the population in the Netherlands in the 19th century, the birth registers of the Catholic parish in Amsterdam and in Leuven have been examined. These two cities belong now to two different countries and to two different provinces. For the research it was important what the inventory of proper names given at baptism was, as well as the influence of parents and godparents on the name of the child.