Simplify the following text for a Grade 6 native English-speaking person.
Original: The first man to witness a live cell under a microscope was Anton van Leeuwenhoek ( although the first man to make a compound microscope was Zacharias Janssen ) , who in 1674 described the algae Spirogyra and named the moving organisms animalcules , meaning `` little animals '' .
Simplified: The first man to look at a live cell under a microscope was Anton van Leeuwenhoek . In 1674 , he described the algae Spirogyra .