Planck was born in Kiel, Holstein, to Johann Julius Wilhelm Planck and his second wife, Emma Patzig. He was baptised with the name of "Karl Ernst Ludwig Marx Planck"; of his given names, "Marx" (a now not used variant of "Markus" or maybe simply an error for "Max", which is actually short for "Maximilian") was indicated as the primary name. However, by the age of ten he signed with the name "Max" and used this for the rest of his life.