In early history people used only one name for their identity. It often denoted a great strength or virtue. After Christianity came to the area most people took Biblical names, usually of persons whom the parents wanted their children to emulate. By the fourteenth century people began to take a second name, usually the first name of their father. With each generation the last name would change.
In Switzerland well into the sixteenth century indexes of persons were in alphabetical order by their first name. as family names began to be used, they would vary within a family and often changed without any formality. Finally in 1822 a mandate was issued by the Bernese government that each political unit should register all citizens. Family names were recorded and only one spelling was considered correct.
German surnames were not standardized until after Napoleon had conquered the area. In all the countries of his conquests he demanded that every person take a permanent surname. Prior to that, people often changed their surname. It was not until about 1875 that the spelling of personal names became standardized in America.
In the early days in Germany, two names were given at the child's baptism. The first name was a saint or a venerated person, such as an emperor or pope. The Lutherans and Reformed used only scriptural saints. Catholic priests required parents to name their child for a saint. The parents would choose a second secular name, which was usually a close relative or friend. Thus everyone in the family could begin with Johann or Maria. The name Johann or Johannes is the most common German given name since the 1200s.
In America, as well as in Europe, the custom of using a saint's forename went out of popularity in the late 1800s. Children were still given two or three names, often of their baptismal sponsors. Many Protestant parents gave their children only one secular name. If a child died in infancy or as a young boy or girl, often a subsequent child would be given exactly the same name.
Sources Used
Brumbaugh, Gaius Marxus. Genealogy of the Brumbach Families, 1913
Harness, Helen Ummel, The Family History of John Ummel (1861-1942) and Ella Lambert (1874-1951), 1999