This is the 962nd most frequent Danish word.
alexander
In Danish, "Alexander" is a male given name of Greek origin, meaning "defender of men."
In this sentence, 'Alexander' is used as a proper noun, referring to a person's name who is the subject and agent in the activity of playing soccer.
Alexander spiller fodbold i parken.
Alexander plays soccer in the park.
Here, 'Alexander' is again a proper noun, but it's introduced as a possessive referring to the author of the books.
Vi læste bøgerne skrevet af Alexander.
We read the books written by Alexander.
In this case, 'Alexander' continues as a proper noun, being the specific individual to whom the action of meeting is directed or related.