Simplify the following text for a Grade 11 native English-speaking person.
Original: After initially heeding her pleas , he went forward anyway , immersing himself for three years drafting and re-drafting the document , which he later persuaded more than 300 prominent workers , Chinese Communist Party members , and intellectuals , to sign .
Simplified: He later got more than 300 prominent workers , Chinese Communist Party members , and intellectuals , to sign the charter .