Original sentence: Indeed, the period from 1585 (when his twin children were born) until 1592 are known as Shakespeare's "lost years" because no evidence survives to show exactly where he was or why he left Stratford for London
Edited sentence: Indeed, the period from 1585 (when his twin children were born) until 1592 (When Robert Greene called him an "upstart crow") are known as Shakespeare's "lost years" because no evidence survives to show exactly where he was or why he left Stratford for London