Simplify the following text for a Grade 8 native English-speaking person.
Original: The first issue was published on 31 March 1901 , by which time the artist had started to sign his work simply Picasso , while before he had signed Pablo Ruiz y Picasso .
Simplified: He shortened his signature in this time to `` Picasso '' only rather than `` Pablo Ruiz y Picasso '' .