Simplify the following text for a Grade 13 native English-speaking person.
Original: He was baptised with the name of Karl Ernst Ludwig Marx Planck ; of his given names , Marx ( a now obsolete variant of Markus or maybe simply an error for Max , which is actually short for Maximilian ) was indicated as the primary name .
Simplified: 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 .