Simplify the following text for a Grade 5 native English-speaking person.
Original: Gian Giacomo Caprotti da Oreno , nicknamed Salai or Il Salaino ( `` The Little Unclean One '' i.e. , the devil ) , entered Leonardo 's household in 1490 .
Simplified: One of his young students was a boy whose name was Gian Giacomo Caprotti da Oreno .